http://www.mangago.me/read-manga/geinaru_tadaima_ire_kawarichuu/?av=2
Its a body switch thing but he uke becomes the seme in the last two chapters
you realize later that he was an uke with former bf
http://www.mangago.me/read-manga/aniki_no_shigoki/
beware contains violence. also you will only see it at the end...
http://www.mangago.me/read-manga/the_trigger/
so he was a male-geisha so it seems he was uke?
http://www.mangago.me/read-manga/mede_shireru_yoru_no_junjou/
same themed. beware a dark one wiht happy ending. the prostiute was uke but with new customer he also is seme. they swithc
http://www.mangago.me/read-manga/orchids_of_endless_nights/
Is there anyone know yaoi manga about the seme who used to be another guy's uke, before he meet the uke??