Remember the scene from the movie Animal House? It was mashed potatoes. That guy stuffed his face with them and then smacked his face to make the contents go out his mouth. He was making a joke? What am I right now? A zit. Get it? You can ignore the music. I did.
As for acne, it is an active infection and it really is better to prevent them or treat them early. I prefer to take a tiny bit of tea tree oil and apply it to any affected areas. This is supposed to have the effect of killing bacteria trapped in the pores.
Weird? I don't know. I guess it would be weird if you made a point of having people watch you do it or something. But I think it is safe to assume everyone does it in private when they have to. I've even heard people say that they found it especially satisfying when the contents actually hit the mirror.