Giannis Antetokounmpo: Check Out My New Sex Bell, 'I'm a Freak in the Sheets!'

Here's NBA superstar Giannis Antetokounmpo proving "Greek Freak" ain't just a nickname ... showing off his Valentine's Day present from his GF -- an on-demand oral sex bell!

And boy, is he happy about it.

"The Freak, he can be a freak on the court and on the sheets, you know what I'm saying?! WOO!!!" Antetokounmpo said.

Yeah, it's a gag gift (no pun intended) -- but we've never seen Giannis so pumped up about anything before!

His GF, Mariah, wasn't a big fan of him showing off their new toy to all his fans -- especially the kids and her fam -- but we're pretty sure she'll get over it.

After all, no doubt Giannis used some of his $100 MILLION contract to hook her up, too.