Is autofellatio safe

you can not give yourself an STD by swallowing your own ejaculate.

the only scenario i can think of where you would spread an STD would be that if you had genital herpes. You could give yourself oral herpes by performing autofellatio, but that is the only thing i can think of.

Autofellatio would be safe from the standpont of getting a sexually transmittable disease--unlike the risk of one person sucking another person's penis. If you were going to suck your penis, or thumb, or any other body part--or a doorknob of anything else--without first making sure it is clean, then of course you could get some infection in the enviornment.

That being said, for most men autofellatio is impossible. Only around 1% can achieve it.