Kevin Durant -- Wanna Suck Like Me? ... Buy My Used Straw!

You can finally share DNA with Kevin Durant ... if the price is right ... because the NBA superstar's actual USED straw has hit the auction block ... for real.

In fact, the straw is the REAL piece of plastic KD sucked from during a SONIC fast food commercial the NBA star shot back in March, when he was promoting the Kevin Durant Signature Slush.

The straw also comes with a certificate of authenticity personally signed by KD that reads, "This is the actual straw from the Candy Slush that Kevin Durant (KD) had on the set of a SONIC commercial shot on March 26, 2015."

There's more ... Sonic is also auctioning off the ACTUAL candy from KD's slush ... which also come with a C.O.A.

Don't worry, it's not some cheap stunt to make a few extra bucks -- the auction benefits the Limeades for Learning program ... which raises money for educational programs across the country.