It's an odd thing really, because it is incredibly erotic with the right person, yet you don't (usually) see or hear the person, and - obviously - you don't touch them.
I joined Second Life (SL) about a year ago and thought I was just playing a version of The Sims, but on-line instead. Being such a huge Sims fan, I went about customising my avatar and making her look cool. For several days, I had no idea what was going on or what I was supposed to do, but lots of guys kept asking to be friends with me. Repeatedly the question of sex kept coming up, but I thought they just wanted to talk about meeting up in real life and that didn't interest me at all.
After a while, I discovered that it is possible to simulate sex between 2 (or more) avatars in SL using animations. Some come as balls you sit on, others are built into objects such as beds, rugs or sofas. Eventually I made friends with a bisexual girl in SL and she was very eager for us to become more heavily involved. She was very good at introducing me to the whole cyber scene very slowly. So we would talk in type chat about kissing and hugging each other and it was surprisingly romantic. We would use poses and animations for this.
Gradually we included other animations and she bought me what can best be described as 'body add-ons' that add erogenous zones to your avatar.
Like other people have said, you type in chat or IMs what you are doing to the other person and you also type in your response to what they do to you. Obviously, during this you masturbate.
Done with the right person - someone with a very active imagination - this is a very powerful and intense form of love-making. In SL, the animations add a visual aspect that is very stimulating.
Cybersex is SL becomes more enhanced if you use a voice chat medium, such as Skype. You actually hear the person as they become more aroused.
Some people have said that cybersex is for the sad, fat, ugly, lonely and freaky people. Yes, it's true. There are plenty of those in SL. But the person who introduced me to cybersex had a long-term male partner in real life. Over the course of our relationship, I saw photos of her, talked to her on Skype and saw her on a webcam (we never had cybersex with webcams). She is a very beautiful woman - not fat, not old, not ugly, not stupid (she's a property lawyer in the US), not lonely. She just likes to explore her sexually. For her, cybersex is just another form of sex.
My current partner in SL is a divorced mother and is also bi with strong gay leanings. Again, she is very beautiful in real life and she works in medicine. What began as friendship in SL developed into love and we plan to meet in real life soon and - hopefully - make our partnership a real life thing. Interestingly, neither of us intended on our friendship becoming more than that. We never planned to have cybersex either, but eventually we did and still do. The fact is, we live about 1/3 of the world apart from each other in real life, yet we know that we have a perfect partnership and the love we have for each other is very real. Our SL relationship is the only relationship we can have right now and it's an exclusive relationship both in SL and real life.
There are a lot of guys who come to SL just for the cybersex. They think all they have to do, is jump on a female avie and whack off. There's much more to it than that. Some of these guys are very young and have no real life sexual experience - some are old and a bit strange.
Some marrried couples come to SL to experience a bit of sexual variety. They might want to try the BDSM scene and SL is a reasonably safe environment to do that as long as you don't reveal too much about your real life to strangers. Some women come to SL to explore their lesbian side. Again, it's a safe environment to do that. You can't be raped in SL because all you have to do is teleport out of a situation you don't like, or even log off. If someone becomes a bother (and it happens from time to time) you can mute them.
Some people who come to SL have limited mobility through disability. Some care for a disabled child or relative and do not have the oportunity to meet people in the real world. In the case of one gay friend, she lives in a country where being gay is illegal. In SL she can have the relationship that she is forbidden to have in her society.
What repeatedly seems to be a big headache is when a married couple come to SL to explore relationships with others outside their real life marriage. Far too often, the guy mistakes the relationships he has with girls in SL as being true love and many real life marriages end because the guy sinks too deeply into the fantasy cybersex of SL. Like I said, done well, it's more intense and fulfilling that real sex. Women tend to see it for what it is - an addition to real life sex. Guy's see it as a replacement for real life sex, or think that the cute avie is an exact representation of the person in real life, which it rarely is. Very few people in SL are better-looking in real life than their avatars.
It's important to note that there are many people who come to SL with no intention or desire to have cybersex. It's just one possible activity within this huge virtual online world. Women outnumber men in SL by something like 5 to 1, so men are somewhat in demand. Of the limited number of guys in SL, maybe one in 60 knows how to do cybersex well. Of those, perhaps 1 in 30 wants a committed relationship with someone. Most of my straight female friends in SL are single due to the lack of decent guys in the game.
Most of the men who don't want to have sex in SL tend to play women avatars, just to divert attention away from them being guys. It's the one place where men can become sex objects pretty much the same way as women can become sex objects in real life.
There are a lot of guys who want to have cybersex in SL, but they put little or no effort into their avatar's appearance and don't even bother to want to learn how to cyber to make a woman happy.
What cybering brings to women is pretty much what they want in real life. It's not just about the act of sex - it's everything that leads up to it. It's about a lot of romance, fantasy and role-play. It's about using your brain as much as your body. Hence there are a lot of women who are married to the 'Wham, bam, thank you ma'am!' sort of guys who come to SL and partake in cybersex to get the experiences they don't get from their beer-swilling, football-watching husbands.
It's very easy to stereotype people who have cybersex - particularly as many of those sad stereotypes do exist. But it isn't really the stereotypes who are doing it - they just WANT to do it. Most people who actually have cybersex are intelligent, educated people and it's not the only thing they ever do in SL.
If you want to see what SL is all about, go to:
http://www.secondlife.com
Just don't expect to be having cybersex with someone who knows what they're doing within the first few weeks of being there and don't assume that SL is only about cybersex.