As the title says, these are my suggestions for the game. These are all opinion based and do not reflect any failings or shortcomings in the game! I just see a lot of promise here and hope to help.
Sex:
Currently the game treats sex as bad. You can exhaust yourself too easily and get shipped back to your last checkpoint. A proposed fix for this is that successfully getting the target to climax restores some libido. This has two major effects on gameplay; if you get the target to climax in the current system you're still gaining arousal thus pretty much guaranteeing your next encounter to cause your climax and a loss of a libido. This pads you against this effect without modifying the way the game plays. It also means that the skill based rhythm game is even more important, as your skill allows you to progress further into an area.
The second thing I'd like to see changed is a delay between changes in pace. Right now a partner can change pace several times in a row, causing the rhythm game to feel more like a guessing game. I could assume that this is just bad luck or lack of skill on my part, but I'd recommend adding a minimum amount of time (15-30 seconds) between pace changes to allow the player to get into a rhythm for a fair amount of time before it gets changed on them.
An item to reduce arousal rate could also be useful to more casual/occupied players, such as 'numbing lubricant', which would allow them to enjoy a scene for longer without getting knocked out for it.
Exploration:
Partners can be far too aggressive with their tracking and don't seem to have much limitation to where and how far they can go. This can lead to situations where you can't touch the ground without getting yoinked up. This is made more problematic by the fact that partners are often faster than the player, and some simply can't be outrun without tricking the AI, like the frogs. I recommend adding a dodge mechanic of some sort, as well as possibly reducing the speed of some of the more mobile partners and giving them some AI that makes grounded partners avoid ledges. This shouldn't affect gangbangs if there's a check for "target in animation I can join", which will allow them to approach normally or even more aggressively while partners that can't join an animation in progress can avoid the area to give less distraction during the minigame.
Bees have some issues with hovering along the ground as they attempt to track the player as well, making getting them into the air very difficult. I would suggest making their ground-grab animation be triggered as part of a 'resting' animation, where the bee finds a place to stop for a moment before rising back into the air. This would mean that any flying bee would be very apparent for travel purposes, while still giving the player the opportunity to trigger the suckling animation either intentionally or accidentally. I only bring this up because while the indicator is very nice, trying to get the bees into the air without accidentally triggering the grounded animation can feel difficult.
Player:
Along with a dodge mechanic, I would appreciate an indicator for when the player is in the 'immune' state, similar to how enemies desaturate for a time after sex. A fading outline or similar would be sufficient to let the player know when they're at risk of entering into another sex scene.
This last one is more or less a kink of mine, and doesn't quite fit with the rest above, but I'll put it out there anyways; I'd like to see cumflation and/or visible cum on the player as the result of sex. Any and all signs of having had sex, especially if it's compounding in intensity based on what and how much the player has done I find really hot. Bonus points if it's locational based on the type of sex the player was having, but this entire concept could prove to be a lot of work that would detract from the progress being made in other (arguably more important) aspects of the game.
That's all I can think to recommend right now, I hope it's not too terribly wordy, but I really enjoyed the demo and think this game is fantastic, so like I said at the start I wanted to contribute if I could.
TL:DR
Restore Libido when partner climaxes
Longer time between pose changes
Reduced arousal rate consumable
Slower/less aggressive partners
Partners approach a scene only if they can join it
Dodge mechanic (preferably both on ground and aerial)
Bees only do grounded grabs when on the ground, and/or fly towards the area above the player rather than along the ground
Iframe indicator