Hi.
Can't help you with the random poking... this is mostly a problem for me when people sneak up behind and jab me in the sides. I do get snappy about this.
I agree that snappiness is not appropriate for family hugs, as the family members feel rejected.
I do have a different idea for family hugs:
Hug them first.
Yep, get in first.
The social principle of this is that the person who initiates the hug (or handshake, or whatever) gets to determine the type and duration of the hug (or handshake, or whatever). This is very useful, as it means you get to choose the frequency, type (maybe sideways hug?) and duration (short) of the contact.
Initiating the hug has another advantage... people will tend to hug you less. This is because NT people often assume that: if a person is not distributing hugs, it is because they don't feel ok, therefore they need to be given more hugs.
If you distribute hugs, the other people think you feel ok, and don't need more hugs.
Hope that makes sense. Does to me.