https://www.youtube.com/watch?v=bsYH4PF1nw4

Short but nice messy scene in the Nickelodeon Valentines Special at 39:12- He looks like he enjoys it too

Its right near the end for those wondering ... around 39 min mark!

There is also a pie in the face at the 30 second mark

There is a lot of messy scenes in this show :

00:30 : pie in the face
04:33 : Jam gunge
20:50 : milkshake over head
and 39:12 : giant final gunge

Sadly blocked