This week, Simon is mostly rubbing his own nipples.

Due to a rare disorder affecting his lungs, Simon must often wear a gas mask whilst out in public.
This is more to protect the general populace than himself; the disorder causes his exhalations to be highly toxic, although with a smell reminiscent of Cillit Bang.
In the Vietnam War, Simon's breath was used to clear vast tracts of jungle. This resulted in the poisoning of thousands of war veterans. Though nobody really cares, because they're fucking American.