Had an idea for Sunflora where the MC is in a really sunny hot area with no water around. He finds a dehydrated Sunflora so desperate for liquids almost feral and she just jumps on him seemingly knowing where a large amount of liquid is and goes right for his dick and sucks it till he cums and the extra liquid would be stored in her breasts for later. But she does not stop there instead continues to try and drink all the liquid in him till he is bone dry. Thankfully the sun sets and forces her to go to sleep till the sun comes back. The MC sees a small pond of cum around her when he leaves and she looks a lot bigger and her breasts look good enough to jump on. Got this idea from the game Conquers Bad Fur Day where she looks like a sunflora and breasts used as a trampoline.
Had another idea where the MC is having sex with a Pokémon and it then evolves while he is still inside her and describes the evolution as if that part of her is evolving to perfectly service his dick and continue to have sex. Don't know which Pokémon could be used for this.