Responses
Yajirushi by Harada? I don't think the uke is a nerd. It's more like he's quiet and he does things for the seme like an errand boy. Just the part where you said the uke overheard the seme say something about him made me think of Yajirushi. Sorry if it's wrong ^^;;
http://www.mangago.zone/read-manga/koi_shitemasen/
I dont know maybe this?
Or something like http://www.mangago.zone/read-manga/porno_superstar/
But then you mentioned about university
That I cant help Σ(っ°Д °;)っ
Yaoi manga, i think its a university setting?. Basically the uke is a nerd and the seme is popular. The seme uses the uke as a lacky (pretty sure the Seme likes him tho). However the uke overhears the seme say that his just using him to his friend (trying to prove that his not gay with the uke...etc). And the uke runs or something. Thanks.