I have syphillis in my penis. my anal and oral swabs were negative. i took 2 bicillin shots in the butt, and 20 hours later i received oral sex on my anus. i made sure my penis was not involved or touched by my partner. could i still have passed it?

Would suggest that both you and your partner be further evaluated by infectious disease specialist.

Probably no risk: syphilis is non-transmissible 24 hours after receiving penicillin, probably sooner. Still, this was very irresponsible. You shouldn't be having sex of any kind until at least a week after treatment, both for a large margin of error and because it might be too soon to know if you had any other STIs -- which of course are common in people with syphilis.