Oral Sex Protection

For cunnilingus (mouth-to-vagina contact) and anilingus (mouth to anus contact):

Use a dental dam, or
Cut open a condom to make a square, and put it between the mouth and the partner’s vagina or anus.

For fellatio (mouth-to-penis contact):

Cover the penis with a non-lubricated latex condom.
Use plastic (polyurethane) condoms, if a partner is allergic to latex.