Krillin and Bulma just stared, wide eyes and jaw dropped, at Goku. They'd been expecting him to grow of course, with how long he had been gone it would have been absurd if he hadn't, but they hadn't expected this, not by a long shot. He was more than twice his size now, and they could only guess at how powerful he had become in all that time of training. Krillin kicked himself now for even thinking of mentioning how he had grown in the time they had been away from each other. He had at least been roughly the same size as Goku before, but now Goku towered over him like everyone else did, it was quite embarrassed and rather disheartening, but his spirits rose when Goku actually noticed and complimented him on his growth spurt, minor though it seemed in comparison to his own.
To Bulma's credit, she actually managed to wait a full ten seconds before she was completely drooling over him. Krillin didn't like how Bulma, even back before, had treated him more like a sex toy than a friend. He'd equally hated how Goku just hadn't minded it. He couldn't exactly blame her now though, seeing Goku like this was making Krillin grow stiff as he thought back to all of their 'training' sessions from before.
He doubted Goku would want to do such a thing now, especially not with him. He probably had all kinds of new experience now, and though Krillin had gone out of his way to train himself in more ways than just combat for when they next met, he feared it wouldn't be nearly enough to please Goku now.
Bulma on the other hand had no such fears. Possibly because she was more focused on how he would be pleasing her than on the other way around, but still. She started flirting about a minute after Goku arrived, and didn't stop until.. Actually Krillin wasn't sure Bulma actually did stop flirting at any point.
Certainly not when Goku was at him warm up training, shirtless and lifting more than everyone else in the room put together; one handed. Krillin couldn't judge her for that though, as he too had devolved into a drooling puddle of lust by that point. It was a wonder neither of them ended up trying to rape him; not that Goku would have actually minded if they had.
Through great, strenuous effort on both of their parts, Krillin and Bulma managed to get through the whole day without tearing of their clothes and demanding a fuck on the spot, something that had been painfully hard not to do around the time Goku was returning from his shower in nothing but his underwear. Both of them had gone to the bathroom to take matters into their own hands at least twice.
When night fell however, they dropped any pretenses they might have had. Rather than fight over who got to have him first, which would only limit the time either of them got, Bulma and Krillin formed a truce. They'd both fuck him together. They doubted that Goku would object to that.
They went to the room Goku would be staying at, and found him sitting cross-legged at the bed, almost as though he had been waiting for them. After a moment or two of looking at his mischievously grinning face, they realized that he had been.
"I was wondering how long you two would take." He said. He'd been teasing them all day, trying to get them to crack and go for it. They could've been fucking from the moment he had arrived, but Goku was impressed they managed to make it so long.
Krillin and Bulma were out of their clothes in a matter of seconds, both sitting on the bed. Goku had spent the whole day teasing them, only fair he calm them down. Goku accepted this, getting on his fours and burying his tongue in Bulma's cunt as his hand gripped and stroked Krillin's cock. Both moaned, but Bulma was clearly getting more pleasure. Goku had been an expert with his tongue before he'd left, and evidently he had somehow gotten even better.
Bulma's legs locked around his head, and she cried out in pleasure in only a few minutes, soaking his face. Goku switched, his fingers probing her pussy as Goku's lips wrapped around Krillin's cock, his tongue swirling around it as he sucke dhis old rival off.
Krillin moaned in constant pleasure as he place his hands on Goku's head, thrusting hard to make sure he took all of his cock. By the time Krillin came, pumping several hot spurts of cum down his throat, Goku was soaking wet and in need of attention.
Luckily, both Krillin and Bulma could provide. Bulma had been hard at work before he'd returned, and had come up with a new invention. Well, she'd come up with several, but the one she'd be using tonight was one of her favorites: a strap-on that, once attached, let the user feel through it like a real cock. It would even push her cum through it so she could cum inside Goku.
Goku was pushed onto his side, his leg lifted and his head pushed into Bulma's tits, which he immediately began to kiss and suck as both rods rammed into him. Bulma moaned loudly as Goku's hot pussy squeezed her toy, Krillin grunted with the effort of forcing his cock into Goku's ass. How was it that he managed to be tighter every single time they fucked? He couldn't understand it.
Goku was in a state of pure bliss as two of his best friends in the world fucked him into oblivion. Bulma, through sheer determination and will power, managed not to cum until she was completely hilted inside Goku's pussy. Once she did, Krillin picked up the pace, hammering harder into Goku's tighter hole to reach his own climax.
When Krillin did reach his glorious orgasm and pumped Goku's anus full of hot seed, they turned the warrior around so they could switch holes. He wouldn't be given any rest until they were satisfied.