Iggy Azalea has a fave twerker when it comes to her #MoBounceChallenge, and even though it's a famous chick ... she wants guys to get in on the action too.

Iggy launched the hashtag campaign -- think Ice Bucket Challenge with more butts, and way less charity. So far, she's says Bebe Rexha's upload is the one she digs the most. However, when you search the hashtag a whole bunch of dudes come up too ... which is fine with Iggy.

When we got her at LAX, she even had male-specific tips. Don't hurt yourselves, fellas.