No, it's not. First of all, sex with a close relative (like brother/sister) is incest, which is illegal everywhere in the US and most other first-world countries. You could spend the rest of your...
NO If you are doing this there is something seriously wrong. Either you are or she is sexualy abusing you / you are her.While I did not, as a young person, masturbate in front of friends or siblings,...
I have heard of boys (brothers or friends) getting together to watch each other masturbate. I personally didn't do this, but apparently, a fair number do this during some experimental stage of youth....