Now, in sex, use a condom. Always use a condom even if its going to be for 5 minutes. A man can pre-cum at any time and you won't feel it. How me and my girlfriend does it, we start off with some slow kissing then it leads onto more and faster kissing. Then, you strip each other and take your cloth off, get on top if her and grind on her if you're a guy. Keep your underwear on or whatever you wear. When you're confident enough, then take off your underwear and slip on a condom. Continue with a little bit of kissing then back away and find her vagina, then take your penis and slide it in and so on. If you don't want her hurt, then before you go doing her vagina, then lick it to make it moist. A vagina is like a rubber band, it can be stretched but only when its wet. If it's dry, it will hurt and be pulled. So give her a few licks here and there then go on with the sex. When you are at the point to erect, make sure your still in her but wearing a condom if you don't want her pregnant. If you want, then continue to slide your penis in and out slowly for mainly your pleaser but hers too. When you're done, wait a little bit to make sure your done with your cum and take it off. Good luck, and don't forget to wear a condom :]
-p.s: from experience btw. trojan condoms work the best, it feels as if its not even there