Heidi Klum Seems to Grab Tom Kaulitz's Crotch While Sunbathing in Cannes

Heidi Klum and Tom Kaulitz caught some rays in Cannes ... and, Klum caught a handful of her man too -- appearing to grab his crotch while they sunbathed together!

The supermodel and her musician husband were lying side-by-side at their hotel in the French city ... bathing suits on, Heidi holding a refreshing drink in her right hand.

She kept her left hand busy, too ... creeping down to Kaulitz's animal-print shorts and pawing right in between her man's legs.

BTW ... Tom returned the favor in kind -- rubbing his love down with lotion to keep her protected from the harsh sun.

Heidi and Tom later threw some clothes back on and left the pool area ... heading for a little more privacy. Unclear if Heidi was able to keep her hands off Tom's shorts when they did get away from prying eyes.

While this blatant PDA may surprise some, it really shouldn't come as too much of a shock with this couple -- who have a history of hooking up in public.

She and Kaulitz were even canoodling in full view of photos in the country earlier this month ... so, it seems their hotel balconies are perfect for Peeping Toms!