Physically, there is no inherent difference between an asexual person and someone who is not asexual. We’ve got the same parts and pieces in the same arrangement and angles as everyone else, and they’ll work the same way, too. The only difference is emotional: Who we feel an urge to use those parts and pieces with. A heterosexual person wants to use them with someone with different parts and pieces, a homosexual wants to use them with someone with matching parts and pieces, a bisexual or pansexual doesn’t really care, and an asexual doesn’t really feel an urge to use them with anyone else.
Asexual males can get erect and ejaculate, and the sperm is normal human male sperm, it’s not some sort of magic sperm that can grow into a clone of the father on its own under the right conditions.
Asexual females can get wet and engorged and can get pregnant, and a pregnancy requires a male contribution, they’re not capable of parthenogenesis.
Asexuals of any sex are capable of orgasm.
Blood fills the spongy tissue of the penis, causing an erection, and the erect penis is-
You mean, how can an asexual man get an erection without being sexually attracted to the person they’re with?
Obviously, the ability to achieve erection and not be sexually attracted to the person the erection will be used with is not an isolated feature unique to asexuals. There are plenty of examples of gay men who have fathered children through natural insemination. There are also plenty of examples of men (gay, straight, or otherwise) who’ve left the bar at last call with whoever was willing to join them. A man clearly does not have to be sexually attracted to someone to be able to have sex with them.
I can only speak for myself here, as I’ve never run a survey of non-virgin asexual males regarding erectile capacity during intercourse, but here goes. Even though I’m not sexually attracted to anyone, my body can and does respond to sexual situations. It’s like downstairs says “Oh, hey, SEX! I know what that is. I’ll go get ready in case you need me.” It’ll react that way to some sex scenes in movies, or to porn, or to knowing that you and your girlfriend had planned on having sex for about a month and now she’s getting into bed with you. It may be a Pavlovian response, where I know that the situation may have the reward of sexual pleasure, so my body gets prepared. Additionally, an erection can be caused by physical stimulation, regardless of the source of that stimulation. Many men have gotten erections from tight underwear, loose underwear, driving on bumpy roads, getting a physical at the doctor, or even just waking up in the morning, and none of those things are generally targets of sexual attraction. When I had sex, there was a decent period of touching and caressing prior to starting intercourse, all of which was arousing.
Some people confuse an getting an erection with sexual attraction. It is very important to note that they are not the same thing. Certainly, an erection can be the result of sexual attraction, but there are many other ways to get one (Like the physical stimulation mentioned above), and most of those other ways will work the same way on an asexual’s penis as on a non-asexual’s penis. When I was in the 7th grade, I used to get an erection every day in math class. Now, I like math and all, but I don’t like it
Oh, and, don’t forget: Despite what President Clinton may have claimed, sex doesn’t necessarily require a penis to be placed within a vagina. So it doesn’t require a functional penis to be involved. It doesn’t even require a penis at all. Hands, mouths, and various devices and implements that may or may not be battery-operated can all be used during sexual activity.
Views on sex vary widely among asexuals. Many asexuals do not hate sex. There are many reasons that an asexual person might have sex. These reasons include (but are not necessarily limited to):
To please their partner.
Because they’ve been told, “Try it, you’ll like it”.
To satisfy their libido.
Because they’re bored.
To find out what it’s like.
Because they want children.
To “fit in” with other people.
Because it feels good.
Because they want to.