Tenshinhan and Piccolo looked at each other, then Piccolo gestured to go outside. Roshi had prepared seals, so Tenshinhan took one as well as a thermos.
Once outside, Tenshinhan held the thermos open with one hand, placed the seal on its body, and kept the cover on the other hand, letting Piccolo explain.
"The technique is actually fairly easy to learn, the hard part is aiming for the container and closing it before the target escapes," the Namekian started.
Trunks realized she'd learn the Mafuba right there and then, and she gave the two men her full focus. Or rather three men, because all of the sudden, there was a second Tenshinhan, which was much weaker than the original if her ki sense was to be trusted.
"Stand aside and watch carefully," the Tenshinhan holding the thermos said, while the other stood in front of him and Piccolo. Trunks moved away to have all three of them in her field of vision, and looked intensely as Piccolo performed the technique on the clone. Tenshinhan didn't close the thermos, and let his clone escape, and that other Tenshinhan placed himself back where he was.
After three more demonstrations, Trunks took a moment to put what she saw into words, hoping to get either man to confirm she understood the technique well. "You use your life energy to envelop the body of your target, and control your own ki as a wave to seal that target away."
"Basically," Tenshinhan agreed. "The difficulty of the technique is to aim, which is why I'm holding the container. Focus is important, and because of that, it leaves you vulnerable to other enemies."
"Tenshinhan-san moved to match Piccolo-san's wave the first time, otherwise he would have missed…?" She wasn't certain, so she looked at Piccolo for confirmation.
Piccolo nodded, 'kid's observant.' "Yes. This clone has little power, so the energy it requires is negligible. The stronger your target, the more energy you'll need to sacrifice for each attempt."
Trunks moved closer to the Tenshinhan with the thermos, ready to give it a try herself, while Piccolo walked away to observe and comment on the attempts. Piccolo also saw Gohan slip out of the window and watch from the roof.
On her first attempt, Trunks used way too much energy, and she gritted her teeth at the strain, but didn't give up. The Tenshinhan clone suffered the wave, and when it came to force the target into the thermos, she couldn't control the flux and the poor clone ended up way into the sea. Piccolo scolded.
"Don't try to kill yourself while practicing! And control your ki better than that."
Trunks nodded, she heard the advice for what it was, and waited patiently for Tenshinhan's clone to come back flying (and wet). She apologized to the copy, then readied herself for a second attempt, for which she used too little energy. The wave didn't take. A lifetime of fighting enemies she couldn't sense, so of course her ki-sensing was far from perfect. She didn't let her frustration take over, and tried again, this time with enough ki to over-take, then with an arguable better control over the wave. Aiming, as they'd said, was the hardest. The poor Tenshinhan double was sent a few dozen meters off target, but at least it wasn't deep into the sea. Tenshinhan himself had moved, trying to catch his clone, but it didn't work.
Eventually she changed positions, putting the target between her and the Tenshinhan holding the thermos. This way, she could see both the target and the container, and that first attempt with the new set up, despite Tenshinhan having to move a couple of meters to match the wave, was successful. She tried twice more, and her accuracy got better.
"Pretty good," Piccolo had to compliment the teenager's efforts.
"Easy to learn, hard to master," Trunks breathed out. She was tired from the constant focus, it started to show. "I will work on accuracy on my own, thank you."
"Master Roshi made several seals so you can keep this one. You use it on the cover once you've trapped your target, else it can escape." Tenshinhan gave her the thermos and the seal to keep. Trunks nodded and went inside to retrieve her jacket, sword and some water for the three of them to drink. She placed the seal and thermos capsule into her capsule case.
"I don't think it'll work on the Cyborgs." Piccolo noted while they rested on the beach after the couple of hours spent trying the technique, and thanked for the bottle of water Trunks brought him.
"Because the Cyborgs do not have ki for us to sense, so projecting our energy on them might not work." Trunks concluded. She could project her life energy on Tenshinhan's clone because she could feel the clone's ki, and wasn't sure how to envelop something she couldn't feel. She'd have to practice on an object while working on her aim.
"But it could work on Cell," The three-eyed man noted. Trying it on the Cyborgs was a gamble, but Cell could be felt and was just as valid as a target.
"Problem is that it knows our techniques, and I know how to counter it." Piccolo was grim, he believed that after the Kamehameha and the Taiyo-ken, it was likely Cell knew what the Mafuba was (as Gero mentioned the robot spies during the tournament where Kami tried using the technique against him). "With luck, we'll only get one chance with the element of surprise."
"This is why we'll watch the news and go to the next city with a plane instead of flying. We didn't feel Trunks get here tonight because you drove, right?"
"Yes, I used my hover-car because I didn't want to ruin the cake."
"So if we use a plane, we can suppress our ki and surprise Cell before it slips away." Piccolo liked the plan, even if planes and hover-cars were slower, it was still a better chance at what he tried that night.
"Oh that's smart." Trunks noted.
She gathered that Tenshinhan and Piccolo were planning to work as a team and perhaps give the Mafuba a chance, if they could catch the monster by surprise. Especially if they seized an opportunity while she and Vegeta were gone. She ended up repressing a yawn. It'd been a long day, she didn't get to take a noon nap, using the technique half a dozen times at least had drained her, and she needed a little rest before going to talk to Vegeta about going into the Room of Spirit and Time. She only noticed Gohan when Piccolo went to join him above the house. Before Tenshinhan walked back inside, she stopped him.
"Tenshinhan-san." She called, and he turned back, expectant. "Bulma-san said you saved her and the baby, when Gero attacked her plane to flee." He confirmed. "I wanted to thank you for that."
"No need to thank me, your mo- Bulma was reckless to come because she wanted to see the Cyborgs, but thanks to her we got to find where his lab was. Can't forgive Vegeta, he's a prick, he didn't lift a finger and kept looking for Gero instead."
"It should have been his role, yes, but that isn't how his mindset works. He-" she sighed, and got just a step closer to speak lower. "He has acknowledged me as his heir. And I saw him trust Bulma-san with his life."
"You think he'll come around." Tenshinhan wasn't convinced, but the teenager mentioning 'his heir' was out of character for Vegeta; perhaps there was something to salvage from the Saiyan after all.
Trunks nodded. She had hopes, even if she was biased by her own desires, she trusted what her mother saw in the Saiyan. "I may be naive, but I have faith. I need to be on my way and rest before trying to convince him to play along with training."
"It's a little crowded, but you can sleep here if you'd like."
Trunks refused the offer, clipping her sword on her back, and extended her hand to shake. "It's too stressful for me to be around so many people, but I appreciate it, Tenshinhan-san. Please relay my gratitude to Chaozu-san for the food, to Master Roshi for his hospitality, and thank you for teaching me tonight."
Tenshinhan shook the offered hand. "All good kiddo. Good luck with Vegeta."
The teenager knew she'd need it. She caught Piccolo's and Gohan's attention to wave goodbye, and she flew off to set up camp for a couple of hours for a well deserved, binder-free rest.
Before meeting Vegeta the next morning, however, she needed to take care of some logistics. Before allowing herself to actually sleep, she took care of her laundry, reorganized her capsules into two separate cases (one she'd take to the Lookout, the other she'd put back in the room she had borrowed at Capsule Corp) and realized being out of her binder was more freeing than it was before. While the reinforced ones adapted to her due to their elasticity, the fabric ones were becoming too tight. And if she'd have to spend a full year with Vegeta, she needed to size up. And stock some specific medical supplies.
After some proper rest, by dawn she got to Central City to find shops which would fit her with new fabric (and adjustable) binders without having to custom make them. It took some bold questions from shop to shop before finding one that specifically sold such items and was open at such ungodly hours. She wasn't much ready for the social discussion the shopkeeper wanted to have with her about 'his gender identity', about doctors that were able to 'help him transition', but she tried staying polite and tried keeping her situation to herself. Especially as she was armed. She was used to being addressed as male, and presenting as male, but she never thought of herself as male. Or of herself as female, for that matter. She just.. didn't think about it. She had other worries.
"Want me to help you get fitted, or you'd prefer a girl helping you, pretty boy?" The middle-aged shopkeeper asked, and Trunks just looked at him with a confused expression for an instant. She shook her head.
"I will do it myself." She came out a little more defensive than she wanted, so she tried to soften a little. "I've been doing this for a little while now, thank you." She got into the cabin to undress and try the chosen items.
"Haven't seen you here before, you're moving in?"
"No, just passing by."
"You're alone? You look young, kid. If you're on the run I can direct you-"
"I am traveling alone, but I am not running away." She moved the curtain to give a cold look to the man, but she went a little overboard with the intimidating aura, judging from the wide eyes of the shopkeeper. She tried to soften, coming out of the dresser with just the binder and her pants. "Look. I appreciate what you are trying to do, and I am certain some people do need the help, but not me. I am neither lost, nor confused, and my reasons for binding are my own."
The shopkeeper looked at Trunks a moment, seeing how muscular the teenager was without a jacket and a shirt on, and nodded, accepting the kid didn't need any help. The sword wasn't for show, clearly. "Ok, I get it. Turn around, it looks a little tight on the shoulders."
With her boundaries respected, even if her paranoid mind had a hard time turning her back on someone she didn't know, she accepted taking the risk and let the man readjust the straps as he'd done thousands of times prior. He had Trunks lift her arms up and then to the sides to see whether it was properly secured to allow all movements, and once it was done, he gave a slight friendly tap on the shoulder. "You're physically active, right? You can move well?"
"Yes, thank you."
"So you mustn't sleep with it on, do not wear it-"
"More than eight hours a day, ideally. I already know all of that as well as washing instructions." Truth is Trunks didn't want to hear all of the precautions she'd heard a thousand times from her mother already, so she went back into the dresser. She deeply missed her mother at that moment. I didn't prepare to be away from Mother for a full year, this is going to be hard.
She ended up buying four of the same model, got them all fitted, and went on her way while wearing one for the day. In a pharmacy, she bought some extra supplies, and then went to West City.
She reached Capsule Corp still in the early morning. At least to Brief standards it was early. Vegeta was already training in the gravity room, but the rest of the compound was still more or less asleep. Her borrowed room's window was still open, so she slid through there to put away the case containing the Time Machines, the car, the computer, the generator and the house, as she figured taking them with her wouldn't be wise. She also left her sword on the bed. Clothes, pharmacy, toiletries, and the thermos with the seal. She looked at her wallet and hesitated, but ended up taking it with her.
She left through the window as she came in, and hovered over the Gravity Room until she could catch Vegeta's eye, giving him a look of defiance, and then flew down to the door. She didn't need to wait long before the Saiyan opened the door with a frown, seeing the teenager meet him with crossed arms and a pointed question.
"How serious are you about surpassing super Saiyan?"
"What kind of stupid question is that, brat?" Vegeta wasn't the kind to appreciate useless interruptions in his training.
"There is a place.."