shoujo

Try
- Biyaku Cafe
- Desire Climax
- Midnight Secretary (this one's actually a josei. but the sex scene is just amazing!!)

^^^definitely try those. And here some more (most of them are josei tho).

http://www.mangago.me/read-manga/misshitsu_no_rakuen/
http://www.mangago.me/read-manga/before_dawn/
http://www.mangago.me/read-manga/yuuwaku_no_bansan/
http://www.mangago.me/read-manga/off_time_no_kemono/ (third chapter is especially hot for me, cause sexy lingerie)
http://www.mangago.me/read-manga/gakuen_ouji/ I think it has hot smutty scenes but I'm not too sure
http://www.mangago.me/read-manga/kimi_wa_seiya_ni_uso_wo_tsuku/
http://www.mangago.me/read-manga/30_year_old_virgin_ol/
http://www.mangago.me/read-manga/honey_x_honey_drops/
http://www.mangago.me/read-manga/erotic_fairy_tales_red_riding_hood/ (and anything by this author)

And if you don't mind seinen/shounen (not hentai!).

http://www.mangago.me/read-manga/sweet_guy/
http://www.mangago.me/read-manga/kimi_wa_midara_na_boku_no_joou/
http://www.mangago.me/read-manga/kuzu_no_honkai/ (there hasn't been any actual sex scene, tho)
http://www.mangago.me/read-manga/minamoto_kun_monogatari/

Thank you <3 (づ￣ ³￣)づ