Asexuality is one such sexual orientation, which is hard to understand by people because most of the world sees love as the stage, which comes next to lust and they can never get the point that love can happen without the involvement of lusty feelings. This is how a materialistic world works. Hence, asexuality has been ignored as a mere mental disease or some kind of an attempt to get rid of sex. Unfortunately, this is so untrue. The feelings of an asexual person are similar to the feelings of any other person except the wavelength can never be matched under the name of sexual desires.
Yes, sexual attractions are quite different from having sex. Some people have sex to relieve their stress and to get rid of their physical arousal due to reflexes. But having, a sexual attraction towards others, make a person a completely non-asexual. Asexuals are defined to be the people who don't have sexual attractions towards others. Which means, they can never get attracted to any person in this world, sexually. But, that doesn't mean, they don't lead a life like every other person. Indeed, they do and they are allowed to do most of the things which a sexually active person does.
First of all, consider an asexual as a fellow human because their body works exactly like yours and they can feel arousal too. This is a very common aspect of the human body. Just because a person's nipples got erected or feel a boner, doesn't mean he is not an asexual person. Understand the fact that arousal can be experienced as a sign of a healthy person.
And yes, they can masturbate too. Do you think a person can masturbate imagining someone or when he/she sexually attracted to others? There are hell lot of reasons for a person to masturbate and also practicing masturbation showcases the clear health status of a person. And come on, what do you expect a person to do to get rid of a huge boner all day? Do think about it, asexuals can masturbate.
An asexual person can have a sex drive or sex urge or sexual arousal too. As being horny is one of the emotions of a person, he/she can have a sex drive to fulfill their sexual desires. They are perfectly allowed to watch porn. I mean, who the hell are we to say what they must do to improve their knowledge of sex or satisfying themselves out of porn? If you don't know, Pornography is one kind of entertainment aspect and there is an industry particularly confined to picture nakedness.
Now you may wonder, how these things can make a person an asexual? What if you come to know, that they can have sex and enjoy sex too? Will you give up on the concept of asexuality? Or do you think that you are not an asexual if you sleep with another person sexually? Indeed, you are still an asexual, if you have sex without sexual attraction. As mentioned earlier, sex doesn't happen only with sexual attractions.
Asexuals can kiss and cuddle too. There is no rule that you can only kiss someone if you have a lust towards them. Some kisses can be out of love and affection. When it comes to asexuals, they are perfectly fine to love another person if they want to. This indeed makes them eligible to kiss, cuddle and fantasize about being with someone, completely immersed in the world of love.
And most importantly, you don't have to judge an asexual person if he/she appreciate someone else's appearances. Of course, looks can never be considered in the life of an asexual because t