First and foremost, make sure you talk to them before you are in the process of getting hot and heavy. Second, you might want to think before you talk about exactly how you want to explain your choice. Be honest about your reasons and clear about what you are and aren’t comfortable doing. If they’re a good match for you, they’ll respect your choice.
“Not right now”

How do I tell the new person I'm dating that I'm not having sex right now?
Want to learn more?
My partner and I want to be intimate but we don't want to have sex right know. Any suggestions? 260-310
There are loads of ways to be intimate without having penis-in-vagina sex. You can experiment with outercourse), toys, touching, anal sex, or oral sex. Remember that if you want to avoid vaginal sex but are okay with anal or oral sex, you’ll still need protection from sexually transmitted infections (STIs). Depending on what parts of your body you are using, condoms, internal condoms with the inner ring removed for anal sex), or a dental dam offer protection against STIs.
Whatever you decide to do, if you’re going to start experimenting, you should definitely talk with your partner before the heat of the moment about how far you plan to go. Then, make sure you both agree that you will stop if things start to heat up too much. If you end up having penis-in-vagina sex and don’t want to be pregnant, you can take emergency contraception to prevent pregnancy before it starts.
Want to learn more?
What if I meet someone and I'm considering changing my mind about not having sex right now?
Either way, you might want to have some condoms and EC on hand (or know how to get them) just in case.
It’s perfectly natural to be attracted to someone, but if you’re seriously considering having sex after a period of abstinence, it’s important to take some time to think about your reasons for waiting. If you realize it’s still important to you not to have sex right now, you should talk to your new partner about your reasons and arrange firm limits on what you’re comfortable doing with them. On the other hand, if you decide you do want to have sex (but you don’t want to get pregnant), it’s a good idea to start looking into a birth control method that’s right for you before you do so since some methods aren’t effective until you’ve been using them for 7 days.
Either way, you might want to have some condoms and EC on hand (or know how to get them) just in case.
Want to learn more?

Heat up your weekends with our best sex tips and so much more.