Updated: Jan 19
Note: This was my response to a question someone asked on the subreddit and I thought it would make a decent post. FDS recommends waiting 3 months before having sex with
FDS recommends waiting 3 months to have sex with someone new so he can prove himself to you, including what he has to offer sexually.
During that time, you can vet for sexual performance and compatibility. You can vet how well he kisses, caresses, snuggles, holds you, and how he is with his hands with neck rubs/foot rubs. You can test his rhythm, the quality, durability and consistency of his erections, and his stamina. Kissing and grinding is great for checking his erection response time as well as his stamina (Bonus points if he's into sports - sports like swimming running soccer are great for sexual stamina!). You should be using this slow build up to gauge his level of generosity. He should absolutely be enthusiastic to prove himself to you as a good mate. Throughout all of these different activities, tell him your preferences and give bits of feedback to see how he handles criticism and how wiling and capable he is to adjust to want you want physically.
Once you have established physical intimacy, you can try oral. We recommend this take place before sex but after commitment is established. You can see how good he is with his mouth, if he can make you orgasm, what he can do with his hands, and how considerate he is. If you go down on him you can vet for any creepy porn behavior such as shoving your head down toward his penis or making gross comments. You can also see the quality and duration of his erections. If he continuously goes soft that's a very bad sign. Ditto for premature ejaculation. I would absolutely make a man make you orgasm before you ever have sex with him. Either from oral or manual. He needs to show he can get you off for you to be willing to have sex with him. This way to you can judge his sexual generosity and also his enthusiasm for making his partner orgasm. Absolutely do not settle for a man who isn't super enthusiastic and turned on! He should I have an erection from going down on you. Also test him by having him finish you but don't give him anything. See how he handles it to vet for pushy rapist behavior. You could also start and stop physical sexual activities and see if he gets angry, cries, pushes, or tries to manipulate you.
This will all help you find someone who is good in bed, cares about giving you pleasure and won't pressure you. Vet hard for any porn behavior. A porn addict will not make it through all of this without repeatedly revealing himself to be a low value creep.
How to avoid going too far once you start and how to tell the guy your boundaries:
You have to be strong and probably have some sort of a deadline that you'll stick to like a restaurant reservation or a time he needs to leave by. I would also do some of my making out and touching in the car at night when he would bring me home from a date. You really shouldn't have to even make any boundaries clear. A man who's actually interested in you isn't going to try to move every touch to sex. If he does, that's a red flag. If he tries to move things further than you're willing to go just tell him this is as far as you're willing to go with the level that you know him and you're still getting comfortable with him. Trust is earned. Tell him you want to move slowly with intimacy so that you are fully comfortable and because you're still getting to know him and trust him.
Say you're making out a little and he starts trying to take your top off. Just use your hand and put it on his hand and stop him and say no. This should be all you need to do. This is another vetting opportunity as well. If he tries again 2 minutes later then he's a pushy creep who isn't listening to you! He has failed.
Here's my response to another commenter about how are not given any sort of conceptual framing for progressing through physical intimacy and up to sex in stages:
I really didn't understand this when I was younger either. Society very much pushes this have sex immediately narrative on women. We're not given any tools to judge a man sexually, even when it comes to our own safety. No information on how to figure out if a guy is a rapey creep. Nothing. There's no longer any narrative about making out, necking, petting or working up to things for months. Or at all. No "going steady" which implies a greater level of physical intimacy based on commitment, trust, time and investment.