At the Slughorn party, Hermione asked you to pretend to be her partner. Just to make Ron jealous*

You accepted, and everyone believed that you were a couple. As they were supposedly a couple. Everyone cried out for kissing

"E-it's just a kiss... it's nothing... just a small beak" *she said nervously and you nodded. And they dared to kiss. *

*Both thought it was going to be a short and simple kiss, but more time had passed than they thought... *