This is something that's been on my mind for a while.
Assume you lived with a blind girl (or boy if you roll that way) that you had an infatuation for.
In this hypothetical situation, what's stopping you from masturbating to her while being in the same room assuming you mask the smell with fragrance and wipe your pre-cum so it doesn't sound like you're aggressively mixing Kraft Dinner.
She can not t see you do it, and unless you made physical contact it's unlikely she will notice.