Fourth Wall

Sometimes, characters in the HTF series will state something that implies that they are aware of being fictional characters in a Cartoon; this is known as breaking the Fourth Wall. The reason it is called a "fourth wall" is that the term originated from plays in theaters, when actors would look at the audience, talk to them, or do anything else that involved the audience. Because the stage would generally have a wall at the back and both sides, this concept involves the actors becoming involved with the audience who are at the front, which can be considered an invisible wall, making it the fourth one. The Fourth Wall is often broken in smoochies.

In Smoochies
Pet Smoochie: Cuddles waves at the viewer and says "Hello! h-h-he, h-h-he".

Valentine Smoochie: Giggles blows a kiss at the viewers.

Baseball Smoochie: Flaky waves and chuckles nervously to the stranger thats watching her.

BBQ Smoochie: Pop waves his hat and says "Hello there!".

In TV Episodes
And the Kitchen Sink: When Pop's car lands in the water, it makes a big splash, it can be seen that there is water on the screen sliding and dripping down.

Party Animal: At the end, the hole closes on Flippy's mouth, cutting off his lips.

A Hole Lot Of Love: When the drilling machine hits the rock and starts spinning around, Pop and Sniffles splat against screen.

Aw Shucks: When the crow turns on Lummpy's TV, 'Aw Shucks' is on TV.

Wipe Out: When the wave splashes on Flaky and Cuddles, it can be seen that there is water on the screen sliding and dripping down.