i love blackhaired ukes's Questions (2)

guysssss ughhhh i can't freaking find this bl manhwa but basically it was like this guy with black hair, he's the uke and he's the mc, but basically him and a lot of the population get isekaied and teleported into this fantasy type world. his seme is his pet mouse (i know it's kinda weird but the ukes cute so i don't mind) and in this fantasy world, the mouse is finally able to transform into this big buff man with white hair. please help friends, i wanna read it very bad (*´Д｀*)

my past websites got taken down so i lost the bookmark but my dumbass doesn't remember the title, i only remember small vague things but the main ones was it was a manhwa, it was a college setting, the seme was those type of guys who doenst like being tied down to a relationship and wanted to keep a fwb thing with the uke, but after breaking the ukes heart from saying that, he realizes how much he likes him and goes on a chasing arc. i think he had black hair, the uke had.... orange? brownish orange? brown? something of the sort... i remember vividly that the uke was drawn with pubic hair and somebody pointed that out in a comment in mangabuddy cuz ukes and ppl in general never get drawn with hair in manhwa and for SOME REASON that's all i can remember. i want to know the ending so badsomeone help plz