My sister is affecting my dreams

So I (M19) have been having dreams of my sister (F18) giving me blowjobs. Essentially what happens in the dreams is I ask her for a blowjob and she gives it to me when our parents aren't home. The dreams have been happening more and more often that it's gotten to the point where I've been masturbating more often then ever and yesterday I moaned someones name out for the first time and it was my sister's. Her room is upstairs almost directly above mine so I'm worried she may hear me and tell my parents and then it'll ruin my home life with my family. And I'm not sure if I should ask her, let alone tell her, as our family is incredibly Catholic. She's nowhere near as Catholic as the rest of the family like me but I'm still worried that if I say anything to her she'll tell our parents and that'll end horribly I know for a fact. What should I do?