You can probably enjoy a blow job with almost no emotional tie to your partner, but screwing requires trust. A romantic, slow approach with someone you know and love will work much better. I managed to contract HIV myself eleven years ago with one incident of unprotected sex. A condom exposed to heat or more than a year old will easily break. Don't carry a condom in your wallet.
Some sex lubricants come in both water and oil based versions.
Make sure you get the condom-friendly water based one. Oils and Vaseline rapidly weaken a condom. You can put lubricant both inside and outside the condom, but don't put it inside other than on the tip, or the whole thing can get so slippery it will pull off. The screwee can't tell if the condom is in place on not. If the screwer notices a sudden increase in pleasure, chances are the condom has come off or broken.