An eterrwiss is a strangely noticable object in the background of an image (usually erotic or pornographic)
something such as cupcakes or " futuramas on"
Though the more odd or outlandish the better
Yeah, i see the guys comical erection through his whities in the picture...but wtf is up with that huge jar of seashells. That's like way too many shells for a" grown" man. That's a raging eterrwiss