No butt crack revealed for me with Kiniki tan through micro. But with some patterns it is a little see through so you can see but crack. I wear vesper pattern even at public pool and no problem (the brief version which has a drawstring). I also wear azure pattern in micro brief at home, even when I am not alone and it is fine. With the micro brief, at the front it is true that you must be aware of what can be seen
I trim it but sometimes you can see the top of my bush... I don’t care when I am in my pool.