Regenbogenkind

doesn't sound weird at all. when i watch hentai (yes i watch hentai) i'm always waiting for just one kiss and end up dissapointed everytime （￣へ￣）
sorry am not of any help tough

I mean, this is a pretty popular yaoi manga and the chances you've read this is high, but Rutta to Kodama is pretty good for what you want, I think. Its been a lil while since I've read it so I'm not completely sure.

http://www.mangago.me/read-manga/rutta_to_kodama/

Not just 'in order to sex' but love - I really like their tender-sweet holding & kissing.
http://www.mangago.me/read-manga/shiro_neko/mf/v01/c005/

This may sound weird but I have seen that the kisses that I find most beautiful are usually in Doujinshis. So here are some of my recommendations for that - http://www.mangago.me/home/mangalist/76167/
I specially recommend trying the 1st one. 1 of my fav kissing scene is from that FMA dj. Gusari's kissing scenes are also drop dead gorgeous! Another one that comes to my mind when you say beautiful kissing scene is "Neon Sign Amber" by Ogeretsu sensei. [SPOILER ALERT] I just LOVED this scene -
http://www.mangago.me/home/photo/446894/

Yay for hentai!!

I actually have an album devoted just to Kisses. If you want click through and if you like the kiss scene you can click the link under the picture for that manga. http://www.mangago.me/home/album/1645/

check out my yaoi comedy list
http://www.mangago.me/home/mangalist/7552/
maybe you`ll find one or two you didn`t kow yet...
for other not sad yaoi just look through my lists, i don`t like sad ones so you won`t find them there^^

I don't know why but I found this extremely hilarious, you should give it a try
http://www.mangago.me/read-manga/kizudarake_no_airabuyuu/

http://www.mangago.me/read-manga/nar_kiss/
http://www.mangago.me/read-manga/gochisousama/
http://www.mangago.me/read-manga/porno_superstar/
http://www.mangago.me/read-manga/ikenai_mousou_fudanshi/
http://www.mangago.me/read-manga/anata_no_tame_nara_doko_made_mo/ (totally recommend)
http://www.mangago.me/read-manga/megane_cafe_glass/ (totally recommend but it's not yaoi)
http://www.mangago.me/read-manga/razoku_no_hanayome/ (totally recommend)
http://www.mangago.me/read-manga/ichi_ni_no_san/
http://www.mangago.me/read-manga/yarichin_bitch_club/ best of the best, honestly
http://www.mangago.me/read-manga/michi_to_no_souguu/
http://www.mangago.me/read-manga/koi_made_hyakurin/