When do I tell them??

My boyfriend of 2 months keeps nudging me to tell my parents about us. I know that if I do I'm gonna have to listen to my drunken father constantly bring up me being a slut and the "oh are you having your boyfriend over later" if I don't wear a bra and my sister will be a bitch about it too. i want to tell them, just not yet. But not telling them is like denying my boyfriend's existence? I'm so stressed help pls