I like the direction of this game. Olgrun looks odd without being too old or ugly enough to be too damn horrific to look at even when paired with a beautiful woman, as in so many Japanese style corruption games. I like the fact it's a mix of fast and slow burn - not much time has passed, but Sereneth is showing both fight and interest and not much x-rated activities have happened. There's also been no hint so far of the bull sharing the Sereneth or beastiality/tentacle stuff. Always nice to see.
Suggestion: keep it slow. No penetration for a good while. Keep on with the slow corruption, the comparisons between the cuck and Olgrun's man bits, maybe have the cuck interrupt things and start acting more suspicious only for the woman to be too curious she starts actively going around the cuck's back to do things with Olgrun?
This is an offhand suggestion, but maybe do more to the cuck? Something to lower Caelen's libido or wound him in some fashion. Make him weaker, but around more often, or something to make for secret sex scenes - things happening right under his nose rather than when he's away or asleep.
Scenes I'd like to see:
More Cum Play!! - more cumming into her underwear, Sereneth realizing what it is, starting to enjoy it. Cum drinking. Maybe some cum-as-ingrediant to food stuff? Might be hard to do considering their journey and cooking over an open fire for three. Cum on her body in places, Caelen noticing, Sereneth having to figure out a way to lie.
More kissing, fingering, foreplay. Keep it slow, make it clear Olgrun has skill as well as a bigger dick going for him. The water from the pool that Olgrun's bringing along could be very useful for that kind of thing.
different clothing? Her clothing is HOT already, but maybe some special clothing to get through portions of the forest. Skintight clothing that shows the men's bulges and accentuates her curves and her pussy? Maybe something in red to show how she has become corrupted? Maybe even just a staff or similar?
(Of course, Naked apron too, but given the setting, I can see that's a late game thing if that)
Milk/size play? Caelen gets shrunk, or Sereneth gets shrunk.Guy can't tell what's going on anymore and is stuck in a carrier as Sereneth and Olgrun have fun, or is almost eaten and has to be rescued. Sereneth gets shrunk and there's a lot of things that could happen. Lactation is self-explanatory, and given the size of her chest...
More shadow play - stuff happening inside the tent and seen only as shadow is interesting. Secret Sex always is.
Good luck with this project!