Finn honestly hadn't been planning nor expecting anything lewd to occur that afternoon.
His heated plant lust, while still lingering, had become more or less under control thanks to Huntress Wizard (and their two shared pets).
In celebration of this, Finn had decided to pass the time until Huntress got back from her visit to Wizard city with a simple walk on the beach, just enjoying being in control of himself.
That is… until he saw something particularly interesting.
He heard it first, a familiar giggle a little ways off. He followed it to the source, finding Susan and Frieda, evidently having just recently returned to the mainlands of Ooo after their trip together, on the beach together. He considered greeting them and stopping for a chat, but instead ended up deciding against it, not wanting to ruin their moment.
Unfortunately it wasn't until the scene before him turned romantic that he realized he was too close to the scene. If he tried to back away, he'd end up alerting them and killing the mood for them, which he simply couldn't do in good conscious.
Finn hid behind a nearby rock, content to wait it out until they were finished… and in the meantime, he figured, may as well watch them.
Frieda leaned in, needing to stand up on her tiptoes to kiss Susan. Susan returned the affection warmly of course, her strong hands moving down her best friend's body. She pulled Frieda closer to her body gently, lifting her up to make maintaining the kiss easier.
Finn bit his lip, conflicted by the sight. Their passion was entrancing to see, but at the same time it felt almost wrong to be seeing it, like he was intruding on something sacred. This feeling of taboo only grew as Susan began to casually strip Frieda down.
The ease with which she dispatched her clothes spoke to how used to doing it she'd likely become when they were traveling together out of sight from others. Frieda's body was slender, but toned, likely having been much more active since leaving to travel with Susan. Finn's stiffness grew as he watched Susan manipulate Frieda's body.
She seemed to have memorized her friend/lover's body in their time together, her fingers sliding along her body and finding her the sensitive weak spots the brought moans from Frieda effortlessly. She only stopped to begin stripping herself down as well.
Finn's member, already stiff, hardened further. Susan's muscled body didn't hide her female aspects, it complimented them. She was by no stretch of the imagination an hourglass figure, but only the blind or phenomenally sarcastic would be able to claim she was unattractive.
Frieda seemed to drool over her body just as much as Finn, if not slightly more. Her long legs weaved around Susan's body, pulling their bodies closer together. Susan's fingers moved down Frieda's body, finding her entrance and pushing into her. Frieda's moans grew louder as Susan began to finger her expertly, her hips bucking against Susan's hand.
Finn couldn't stop himself, the heat he'd had rather under control beginning to bubble back up inside. He moved down his pants and began to stroke himself to the sight, somewhat guilty but unable to stop himself.
Frieda's moans only grew louder as Susan got more aggressive, beginning to suck on her neck as her fingers pumped harder into her; causing her entire body to move back and forth as she did.
Frieda bit her lip as she was forced closer and closer to her peak, wanting it badly. When Susan stopped before she could go over the edge, she couldn't stop herself from actually whimpering.
Finn tensed when she did, realizing that she had stopped because she'd spotted him. He turned for a tactical retreat, only for Susan to be standing before him when he did. Fuck she was fast. Susan reached down and pulled him up.
Now, between his normal abilities and his plant powers, he could definitely have subdued her and avoided any repercussions for this peeping, but opted against it.
He figured it was fair enough whatever happened next. Given Susan's strength and Frieda's gizmos, Finn couldn't even guess what way he'd been dropped.
He was somewhat caught off guard when, instead of Susan overarm throwing him into the ocean so he skipped like a rock until he collided into a whale, he was placed down gently next to Frieda, who gave him a cheeky grin.
"Uh.." Was all Finn could get out before Frieda, well aware of what Finn would be thinking, answered his question before he could ask it.
"I.. never really got to.. You know, 'experiment' at all back on the islands," she explained, "Susan got to while she was with the Hyoomen, and said she'd let me try it to. Susan said you were one of the only ones she trusted for it though. We were planning to come find you later, but it looks like you found us instead."
Finn's eyes widened in surprise at this as he looked between the two of them, expecting them to burst into laughter and proceed to punt him while his guard was down, but no, they were evidently dead serious.
His grin growing to match theirs, Finn nodded, "That.. sounds great."
Finn wasn't sure what luck deity he'd befriended that had allowed for this, but he wasn't about to question it when his member was still stiff as a board.
Frieda, after looking to Susan again just to be sure, and getting a nod of approval, moved her head down to gently kiss Finn's tip, followed by her tongue moving along it gently. Finn moaned as Susan moved back and sit down to watch. Wanting her to have a little fun to, he let his hands extending into the ground as plants.
Said plants sprouted up on either side of Susan, coiling around her ankles to force her legs apart before a third and fourth vine buried themselves inside of her pussy; already wet from anticipating the fun with Frieda; and evidently getting from watching Frieda begin to suck on Finn's member.
She blushed deeply at the thought of being aroused by watching her combination BF and GF do things with other people, and opted not to think about it right now and just ride the wave, enjoying the pleasure. Frieda was doing the same, head bobbing happily along Finn's member as he encouraged her to keep going.
She wanted to try more though, and when Finn assured her he was lubricated, she moved up into his lap. Finn, having caught up by now to Susan's unknown kink, turned Frieda around so she was facing Susan as he thrust up into her, letting Susan see his cock stretching her tight cunt, see her expression contort with pleasure as she was fucked.
Finn couldn't tell who of them ended up cumming faster from this, but neither of them wanted to stop after round one, that was for sure.