I would simply like to know if there are any risk in contracting HIV from direct genital to genital frottage (i.e-no penetration) thank you?

You're fine. That's a safe practice and many couples find this very satisfying -- the touch is there, and it's safe, respecting one another's health.
Unlikely but possibl. It is unlikely for you to contract HIV in this manner but if there is any microtrauma and body fluid involved in the activities, it is not entirely impossible.