How do you unlock pants on fancy pants 2

There will be a snail and a hole in each level. Kick that snail into that hole.
You can identify it's a level or not. After you jump into the hole on the beginning, you would hear the music. And after you go into another door(not the beehive one), you would hear another music that is different than the last one. The music you now is NOT a level. Hope my answer helped you.