Responses
http://www.mangago.me/read-manga/12_ji_kara_hajimaru/
Hope this is the one
This is similar too
http://www.mangago.me/read-manga/puchitto_hajiketa/
its about a guy who tried being a uke once but i guess it hurt to bad. so he says hes only a topper not a bottom. but he had an ex boyfriend who is also a topper. they keep meeting up and him and the ex keep trying to take the seme position?