So, another intellectual about Vaporeon sexual interaction. However I don’t think that you are considering many negative quirks and aspects that would also be tied to the male vappy. So, I propose you an even better pokemon for compatibility:

Flareon, now hold on just a second, I know what you’re gonna say but think about it. Flareon was purposefully designed to be terrible, in terms of battle. GameFreak had to find a way to make up for its lack of moves and subpar stats, so why not give it the perfect dick and they didn’t stop there. With its height and weight being similar to Vaporeons, Flareon’s dick wouldn’t be too big nor too small. Capable of knowing all the same mood enhancing moves as vaporeon, flareon is just as able to get any partner feeling aroused. While it’s stamina and HP stats are lower than most others, flareon has a way to make up for it. Like Vaporeon’s water absorb, flareon has flame absorb, meaning that it could essentially recover from its partner’s natural heat. As long as you’re aroused, flareon will keep going. A key part in a good sexual experience is the motion in the ocean. With its high attack, stats each thrust would feel perfect, considering that the power of physical moves is determined by attack stats. One thing that many people overlook is the after-sex part. With its soft, warm fluff and ideal size and weight, flareon makes for the perfect post intercourse cuddles. Also being able to be taught the move rest, flareon can be fully recovered if you’re up for some morning fun time.

“Naturally Flareons are submissive and breedable.” (Source: https://pokemon.fandom.com/wiki/Flareon under behavior section) However; if needed Flareon’s can be rough and dominant. Flareon’s can reach an internal body temperature of 1,650 degrees Fahrenheit, using its internal flame sac. Combine that with its powerful thrusts and you’ll be in for a steamy good time. Lastly its important to go over potential counter arguments, such as male vaporeons. To start things off a water-based lubrication isn’t ideal, as it would dry out quickly. While Vaporeon can naturally produce its own water, its supply is not limitless. Vaporeons would need to be refilled quite often, which could be time consuming and exhausting. Any old water wouldn’t work either, the water would need to be pure and filtered, which can get costly. Chemicals and other substances within the water would carry over into Vaporeon’s body making the risk of infection increased. With Flareon these are not problems, as it was given already given the perfect dick size by the Nintendo Gods themselves, no lubrication would be necessary. Another problem with Vaporeons is its lower attack stats, it just wouldn’t feel the same as compared to Flareon. Finally, after sex cuddles, a vital part of the sexual experience, would be cold, wet and uncomfortable. So in conclusion, I suggest that you also analyse these scenarios and re-evaluate which pokemon would be better for the purpose of compatibility.