A variation of it us used to signify a BJ. Is this the info you're seeking?

Are you talking about ASL?  I don't know for sure but I don't think there is anythingi established for the hearing impaired in this industry.  I could be wrong.

Many years ago I lived with a woman who was slightly hearing impaired.  Most of her other friends were more severely hearing impaired.  Trust me, they have their own signs for anything and everything intimate!  

D.

I haven't seen an ad offering sign language but my guess is that it's a handjob if you saw it in a body rub or massage ad.

It is in the list of options on p411 and this is how it's defined;

 
"Sign Language

Provider can speak in sign language (for the hearing impaired)."

Doesn't seem like anything sexual is meant by it. Just a straight forward kinda thing.
xo