Latex condoms are the old standby, and now come in many different sizes, colors, textures, and flavors. The newer polyurethane Avanti condom is at least as hardy as latex and is safe to use with oil-based lubes. For maximum safety, fingers or fists going into vaginas or butts should be covered with a latex glove. Oral sex is the eye of a hurricane of controversy. Giving head without a condom is not risk-free, although it is certainly safer than unprotected fucking.
Oral sex can also spread diseases like gonorrhea, chlamydia, herpes, and genital warts.
Use a dental dam, plastic wrap, or a Reality condom for asslicking. If you are going down on a woman, a dental dam or plastic wrap should cover the opening of the vagina. There's more to kinky sex than just our genitals. Luckily for us, if we use common sense, most SM activities are safer than unsafe sex. Gloves should be worn for activities that involve blood.