What's on your mug?

or slipped the tounge, when people are kissing without tounges then one of them slides their tounge into the other's mouth

Jane got pissed when Tom suddenly kissed her and tried slipping the tounge.

By Dawn

this is pretty self-explanatory. I have no idea why Dawn felt the need to define it for us.

Slipping the tongue = Slipping the tongue.

By *tt