i think the mc was a girl

the art was quite good and the girl drawed quite sexy(so all the characters)

basically the girl was concsious of her body(she have big breast and she also a beauty) and quite anxious with her bf. She kinda want to have sex with her boyfriend i think. But both are too shy on doing it.

her boyfriend was quite normal , but i think he looks quite handsome because the artistdrawing was good.

i think the latest chapter i read, she have rival who seems want to steal her boyfriend and they got into a fight. her rival was quite seductive even try to sleep with her bf just for playing around (her bf refuse her advance and she began liking him for real).

i think the manga have this mahiro or mashiro thing in the title , try search google but for no avail.

Maybe it was Junai Toro Trip?