1) I think Sasa sells empty spray bottles (those that use air,
similar to perfume type of sprays). Be creative. You can add mix
soap with some insecticide, curry powder, pepper powder, etc etc,
and dissolve in water. Then pour into the bottle and bring it out.
Very cheap. One bottle a dollar I think
2) That Salonpas spray up there, or this

Scare the guy with harmless mineral water.
Alternatively, get insect repellent to repel him. For greater
effect, spray into a lighted lighter to hv a flame thrower
effect
3) Take out your camera phone to video tape him down since he likes
to be an exhibitionist. Then go to mata show them. Upload a 2nd
version on youtube.