What happens if the condom slips off???
First, you retrieve and properly dispose of the slipped condom. Sometimes, if the condom slips off, it gets stuck in the vagina or rectum. If it's in the vagina, you or your partner can reach in and pull it out. Do so carefully to minimize spilling its contents. If the condom is in the rectum, you could try to remove it carefully with a finger, or you could hope to pass it (but that can take a while), or you might go to the emergency room to have it removed.
If you are female and not on any other contraceptive, you should go to a clinic and get emergency contraception. In some places, you can get it at the pharmacy or chemist shop, but this varies by region. Do this within 120 hours of the incident. Timing is essential! The faster you get the emergency contraception, the more effective it is. Emergency contraception is not the same as as the abortion pill. It does not terminate a pregnancy in progress. Instead, it's a high dose of hormones that tell your body not to release an egg, preventing fertilization from even occurring.
Whether male or female, both you and your partner need to be current with STD screens, especially if you have had a condom failure. If you have not been tested, but have experienced recent condom failure, wait 4 days (and abstain while waiting) and then get tested for syphilis, chlamydia and gonorrhea. Four days is enough incubation time to allow an accurate result. If you test positive, then you can receive treatment for the infection (also abstain during treatments). Then get follow-up tests. One month after the incident, get screened for HIV. Then repeat the HIV screen at 3 months after the incident. HIV has a long incubation, and it can take up to 6 months before an infected person tests positive (though most tests will be valid at 3 months). After that, as with any sexually active person, you should incorporate semiannual STD screens into your health routine.