In order to avoid this, level with your guy. Tell him you think things are moving too quickly and let him know YOUR thoughts on how things should progress. If you're specific about what you're game for (and what you're not), and he's a decent guy -- one who is worthy of you, your love and your body, then he will RESPECT YOUR DECISIONS -- regardless of whether they necessarily jibe with his.

If he disses your ideas, or makes you feel uncomfortable or silly, dump him -- anyone who doesn't respect your feelings is NOT, I repeat NOT the guy for you. Respect yourself and others will respect you back.