http://www.mangago.me/read-manga/joou_to_shitateya/
Try this one idk if you've read it already. And most of this author's work have these type of semes
Check out mangas by Mishima Kazuhiko. Her semes are usually younger and uke-like :)
Almost everything from Scarlet Beriko xD She likes "fragile" semes. My favs are:
http://www.mangago.me/read-manga/jackass_sawatte_ii_tte_dare_ga_itta_yo/
http://www.mangago.me/read-manga/yondaime_ooyamato_tatsuyuki/
http://www.mangago.me/read-manga/amefurashi_shunu_ni_shippori_to_nureru_ooedo_renaitan/
ONE OR TWO MANGAS IS NOT ENOUGH!
ヽ(`Д´)ﾉ
i had a chock-full of list of them. anyone feel free to subscribe for updates http://www.mangago.me/home/mangalist/22922/
do you guys know any yaoi manga that has the uke looking guy as the seme? you know they seem kind of frail and thin but they are actually strong and can top