Do girls and boys ever masturbate together or teach each other?

So this is a serious question. Do girls and boys ever masturbate together or teach each other?
The reason I ask is because me and my friends did all the time at sleepovers. I remember it first started when we were nine years old when we would show each other our privates and discuss masturbation techniques and talk about what things we would rub ourselves on like teddy bears and other stuffed creatures. We were a group of four girls and learned so much from the experiences. However this subject kinda came up when I was out with a three work friends recently and they were shocked that me and my friends had done these things when we were younger. So were we just weird or is it commonplace? 

Sure we do. Maybe not all, but me and my girl friends sure do.
We have sleepovers that end up with most of us naked, humping our stuffed animals. We have hiking trips which somehow ends with masturbating. We got our cousins/sisters/girl friends that share different ways of masturbation. We started this when we were 10 years old.
Girls (at least the girls I know) are generally more open with each other about this stuff, as there's so many ways/techniques we just want to help each other try new things and discover what we like best.

Yes I often rubbed one out with my girlfriends so much fun to see who can cum first

Yes! I have masturbated with my sister, friends and cousins, we all enjoyed it everytime.

I like to do that. It’s so sexy

I was an only child but now I have three kids of my own and too many times I find them behaving inappropiately with one another. And they always give me an excuse as if I am five years old. I want to know what and what not is going on. How far are the interactions going and what do I do to stop this before it is too late. Do I yell and punish. Talk calmly and correct. It is too much and I request relief with professionsal resolve. I do not want interbred grandbabies.