I don't try to gear my self up to be horny, sometimes I just am. Sometimes I'll jerk off 2 or 3 times in a couple hours, but I'll jerk off every day pretty much. I've found that if I "think too much" about getting horny, it becomes more difficult. Less thinking and more imagining.
Yes, my mom caught me 3 times. Always in the shower and the doors were clear glass so there was no hiding it. One of those times I was just starting to cum. I'm almost positive that she saw me every time because she looked in my direction. She never said anything about it though.
I like that you said you "personally don't like" instead of offended by certain words. I like vagina. I love pussy! I don't know why but pussy sounds sexy to me. Call it whatever you want. I ask women what they prefer me to call it.
I have had sex with 2 female cousins. It was great! We're not going to have kids or get married. At least in my experience there have been no problems. I don't regret it or feel weird about it at all. Everyone is different and there is always the chance that it ends up badly.