a yaoi manga where the uke is a virgin and his first time was hardcore
Ootsuki Mui has stories like that.
For example: Stay Gold-Koi no Lesson A to Z. (It does depend on how hardcore you want tho)
For more hardcore maybe you would like: Hakui no Shihaisha. Author has alot of stories like this.
Second story http://www.mangago.zone/read-manga/ikujinashi_no_shiawase/
http://www.mangago.zone/home/mangalist/56234/
a yaoi manga where the uke is a virgin and his first time was hardcore