Is this a sign a married man is coming onto you?

So I know I have mentioned on here before that my mom's best friend's husband recently starting poking me, touching my thigh under the table (but i always thought it was because of pure coincidence or playful gesture having to do with jokes or funny incidents) but today when I am over it escalated more to him lightly tapping me on the butt two times when he passed me by...i gave him, "the stare" and he started feeling uneasy right away and mumbled something. Could a man just be joking when he taps a 22 year old girl on the butt or does that mean he wants something. I told me mom and she said, "who knows...." is she in denial or whats going on? I am serious with these questions...could this STILL be innocent?
ps...please mention your age so i know who's responding to me and how serious and relevant the responses are :)

the weirdest thing is that he's never super nice to me when everyone is cautious and around...he tries to not talk to me but during these weird times he sends out these signals

the worst part about this is that it's kind of turning me on and I wait until he makes the next move...but on the other hand i don't like it and it's wrong..and I don't know what to do