Toriel snaps her fingers and her clothes disappear
and you start feeling weird.
You view has changed.
You look down and see that your legs have been replaced with big white furry balls.
You start panicking.
Toriel: don't worry Frisk, you'll love this
The white fur spreads more up your body and your arms just go into your body.
Toriel rubs you and you cough up some cum
Finally the transformation is completed as your head is turned into a cock head
Toriel: Now you get to stay with me forever