While companies differ one from the other, the Law about sexual harassment is NOT a double-standard.
If you think there is a double-standard, then perhaps it is just in your head.
At the very least, tell them you do not appreciate that and that they need to stop smacking you.
If she continues, tell her that this is sexual harassment and she needs to stop .. ask her how SHE would feel if you started smacking HER boobs.
And then if she continues, then you go to Human Relations/Personnel.
And, right, you cannot grab her boobs.
What she is doing is NOT allowable.
What applies for women has to also apply for men .. THAT is what "women's lib" is about ... equality in all ways for BOTH sexes.
I am a woman, btw.