Amber Rose Leaves Concert with 21 Savage

Amber Rose appears to have at least one bush backer in rapper 21 Savage ... after they left a show together in L.A.

We got them Thursday night walking out of the Belasco Theater where there was a music show put on by Red Bull. They got into his red Ferrari, and since it only seats 2 ... the math was looking good for a hookup.

Amber's not shy ... she claims she hasn't had any sex partners this year because work's kept her so busy, there's "no time for penis." Raises the question: for whom is she bringing that bush back?