Condoms are very effective for preventing HIV transmission. When condoms don't work, it's mostly due to improper use.  Approximately two percent of condoms tear during use. Nearly all of these condom failures are caused by human error, like not using enough lube or by creating tears long, sharp, or jagged fingernails.

• The average male ejaculates at approximately 28 miles per hour. That's faster than MUNI. Ejaculating inside a condom is fine, but if the sperm hits an air pocket, it could blow a hole through the end of the condom. To prevent this, be sure there is no air trapped in the condom before rolling it on to the penis. Do this by pinching the end with your fingers, which also leaves space for semen to collect.

• Even though everyone is all eco-conscious these days, with condoms, it's not a good idea to recycle. Use each condom only once. If the condom slips off during sex, do not put it back on. When playing in groups, use only condom per partner.

• Just as condoms expire, they are also only meant to last for 20 minutes of rigorous use. For extended play sessions, take a quick break and begin again with a fresh condom. This is especially important information for guys using crystal meth during sex, where it's easy to lose track of time. (A tip to watch the time: if porn is part of your background ambience, remember the average scene in a porn movie lasts about 20 minutes.)

• Be honest about your size, despite what your online profile says. A condom that's too small for your dick might break during sex. Likewise, a condom that's too big can fall off, and even fall into your partner's hole. If someone says that they can’t get hard with a condom on or that they are too big for a condom, try different brands. Larger condoms, snugger fit condoms, and synthetic non-latex polyurethane condoms are all available at the STOP AIDS outreach office on 207 Sanchez Street.

• Lube is important. Especially with condoms, since friction can cause tears in the anal tissue. For latex condoms, use only water- or silicone-based lube. Don't use oils of any sort - baby oil, Crisco, cooking oil, Vaseline, or other petroleum-based products with latex, as the condom will easily break. Some petroleum-based lubes are great for beating off but at the same time are like Kryptonite to condoms.

• Dispose of condoms properly. Tie te, just like many San Francisco relationships. Check the expiration date on the back.

• Like many men, condoms are strong, but also delicate. Be careful when openingthe wrapper so not to rip it. he end into a knot and toss it in the garbage. Do not flush condoms down the toilet, as they can clog pipes and other plumbing.

• Do it like a Boy Scout: be prepared! Keep condoms and lube handy and in good supply. Store them some place cool, dry, out of direct sunlight, and not under pressure (like your wallet or back pocket).

See also Condom Types.