Love Quest — Lily Hoshino

Rejected by the girl of his dreams for some guy named Moriya, Kazunori
Akabane is royally ticked off when he unknowingly collides with his
rival in the school hallway. Unexpectedly, the accident warps Akabane
and Moriya to a magical realm full of wizards, princesses, and
monsters! But much to Akabane's chagrin, the key to the classmates'
survival in this world is...the exchange of their bodily fluids! Can
Akabane ever get used to the idea of swapping spit with a guy?!