First of all I just want to say religion in general is okay I'm not here to start anything about that. Now with that in mind imo it's stuff like this that causes mental illness later in life. All that sexual repression of course something bad will happen. Then what? Punish you b/c you couldn't have a release? In front of your whole fam? That seems pretty severe to me. Now I may get a lot of flack for this but for the sake of your life just try releasing to something normal. By that I mean someone not in the fam that you find attractive. (not trying to belittle btw just defining what I meant there) If you feel guilt after you can always apologize to God (I'm assuming that's where the fear stems from as well as mom). It is he who holds the power to forgive imo. Now this healing will take time and won't be easy right away. You're counteracting a lot of psychological damage done over a long period of time. If people give you crap about this feel free to msg me. It's not worth your life or sanity just to be "pure" imo.