User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-74.110.108.150-20141120150126/@comment-24468758-20141121072436

Rias kissed Issei the first time at the end of Vol.1 but her first kiss was at the end of Vol.2, so I would count that as Akeno's first kiss. Only the loli girls didn't kiss Issei in their respective volumes as well as Rose, but Rose is a special case as she just started to fall for Issei recently.