Drip Drop into Pure Romance

Momoko and her boyfriend Tetsu have been together for half a year, but they still haven't even shared their first kiss. Tetsu is constantly worried about whether his advances are going to offend Momo, while she is too shy to tell him she wants to take things further. One night, she receives a mysterious e-mail and makes a wish. After that, her mouth becomes incredibly senstitive to all kinds of stimulation! How will this affect her relationship with Tetsu!?