jacks off
When Spider-Man rubs his wrist using his hand until a white sticky substance is released, often called, "His Webbing". Spidey often uses this "Webbing" as a form of transportation among other things in order to save the day. This is why when Spider-Man isn't horny, the day does not get saved.
Spider-Man isn't saving the day? He's probably not jacking off.
Webbing is just jacking off, but with style.
When Spider-Man is jacking off, the city gets saved.