To practice safe sex means to keep the bodily fluids that can transmit STDs totally separate (blood, semen and vaginal fluid). Being prepared shows that you are considerate and that you care about yourself.
Viruses and bacteria cannot pass through latex (unless broken!!).
Use condoms every time you have either vaginal or anal intercourse.
Use flavored condoms, dental dams or gloves as a barrier during all oral contact (oral/vaginal, oral/penis or oral/anal).
Put condoms on sex toys used by more than one person for any type of penetration or on toys that go from anus to vagina.
Use only water- or silicone-based lubricants with latex (including condoms, gloves, dams, cots and diaphragms). Never use oil or petroleum-based products with latex, these can break down latex and render it ineffective!
Dispose of gloves, condoms and dental dams properly. Turn gloves and condoms inside out as you pull them off and drop in the trash.
Never reuse condoms.
Drugs and alcohol can impair your judgment. Have sex when you're sober.
Clean your sex toys with antibacterial soap or a toy cleaner after each use.
Use gloves for any contact with the vagina or anus of your partner. Be sure to use a fresh glove after touching her anus.
Never touch your partner's anus and then touch her vagina, whether with your hand, sex toy or tongue. Wash your hands with an antibacterial soap and put a fresh condom on the sex toys.
If your partner has an infection, yeast, bacterial or urinary tract, see a doctor.
What if we're monogamous? For two people who have sex exclusively with each other, here are some recommended guidelines:
Use latex barriers every time you have sex for six months.
After six months, both of you should be tested for STDs, such as herpes, HIV and hepatitis C. If you both test negative, and there are no other bacterial infections, such as Chlamydia, you and your partner may decide to have barrier-free sex.
Remember this presumes that you trust your partner is truly monogamous.