Donald Sterling -- I Only Said Racist Things ... TO GET LAID!!

Donald Sterling is telling friends ... he only made racist comments to V. Stiviano because he thought it would persuade her to have sex with him ... TMZ Sports has learned.

It sounds crazy ... but we're told Sterling is adamant the comments he made to V. during the rant posted on TMZ Sports were supposed to act as some kind of aphrodisiac to get her in the mood.

Safe to say the plan backfired ... in a big way.

Sterling is telling friends ... he was so desperate to bang Stiviano, he was willing to say ANYTHING to get her to consent to some old man humpin' ... and no man should be judged by what he says to get laid.

As for Stiviano, she insists she NEVER had a sexual relationship with Sterling.