Answer from Dr. Locker
As long as you have both already consented to having sex with each other, then either may insert the penis. It’s a matter of personal preferences. Because the woman receives the penis, she may want to have more control over its insertion. Also, she probably knows her introitus (vaginal opening) more intimately the man does; so, she will know if she is lubricated enough, her preferred angle of penetration, and if she needs to hold her labia far apart to allow the penis to enter. Yet, if the man enjoys the feeling of guiding his erection into her, then he may prefer to do it. Some men like to tease a woman by just putting the head in at first. That man would want to do it on his own, so he can play while he puts it in. If a man can not quite find the best angle of entry, or if he’s not aware that he may need to hold her labia to the side to enter, then she can certainly lend a hand. There’s no reason why they can't both help.
If the man is not sure how to do it, here are tips: First touch the entrance of her vagina with your fingers to feel if she is lubricated. If she is not lubricated enough yet, then use some of your saliva to lubricate her vagina, or a store bought lubricant that is condom compatible -- or have more foreplay! If she is well lubricated, then part her labia with the fingers of one hand. Try to find an angle of entry that allows your penis to gently slide into the vagina. If the penis does not slide, guide it with your other hand, as you try to move your position to adjust to the best angle of entry. All during the process, continue kissing and touching, to keep her (and your) level of arousal high. Also, make a deal that the partner who inserts it, needs to also check that the condom is on properly.
During intercourse, if when changing positions the penis comes out, the person who has the easiest and fastest access to it can put it back in. First come, first serve. However: Some men have a fear that if the woman is on top and his penis comes out, then she will thrust back down hard, missing vaginal opening, slamming his erection into her body – which could injure his penis. If that’s your fear, then let her know before sex, that you would like the job of reinsertion - when she’s on top - to be all yours, or at least tell her that you will require that she uses her hands to slowly and carefully reinsert it.
Copyright © Dr. Sari Locker www.sarilocker.com