Young Bad Education
Read this, then read the sequel 'Young, Good Boyfriend'. The sequel looks good. Not sure about this one, but you need to read it before the other anyway.
Young Good Boyfriend
Sequel to 'Young Bad Education'. Looks pretty good! You need to be in the mood for reading about a heartwarming, healthy relationship, though.
Prince Charming
Read this for a change to the typical fluffy, romantic, monogamous couple type stories. See how you feel about all the 'free love' being shared around. Personally, I suspect that it may actually be a relatively realistic depiction of the way young gay men act.
Evergreen Days
Apparently, this is a REALISTIC student × teacher story - sounds interesting. The art looks good and the h scenes too.
17 Seito
I feel the need to read this, to see which side of the comments section I'm in agreement with lol. Apparently, this is quite realistic, (apart from the rape survivor falling in love with their rapist thing). It's apparently different from other manga that use the same trope, though, in that the rapist makes a sincere, thorough and continuous attempt to apologise and redeem himself. And when I say continuous, I mean that he does so for 10 chapters straight, right until the end of the manga. I think that's pretty much unheard of in yaoi, so at the very least that's a plus point (or maybe a star?) from me. Note: From some of their other works, I know that this mangaka can do bittersweet realism well, so I'm hoping that this'll be more of the same...
Kenban no Ue no Caress