Air Shaft
In the act of scissoring one girl shifts up a bit and rips ass in the other girl's vag thus causing a vibrating sensation on the clitoris.
When the two girls were scissoring the one had gas and performed an air shaft.
Shaft-airing
When you get too hot so you lay in bed naked.
Mum: What are you doing?
Me- Just shaft-airing, Mum
Me- Just shaft-airing, Mum