dojin (brown hair, big orange eyes) is uke. taehee (pale greenish hair with ahoge, long lashes) is seme. jinju (the red hair, big purple eyes girl) is dojin's ex and taehee's now-reluctant friend.
baek sahn, the blue/gray haired guy in the first few panels in ch 53 is dojin's "best friend". taehwan (black hair with ahoge) is taehee (the seme)'s big brother and dojin's friend. yeonwu (blackish hair with green tints, small pupils) is taehee's friend who is NOT a homophobe. these two aren't relevant to this chapter, though.
people tend to mix yeonwu and sahn up. just remember, yeonwu is a good guy, sahn isn't.
GUYS IM BAD WITH NAMES IDK WHO IS WHO!! I’m confuse!!! (〜 ̄△ ̄)〜