GIRLS I NEED YOUR HELP

So, this boy and I have been talking for awhile. I really feel like I need/want sex and him and I are on the same level with a lot of things. My mum would NEVER let me sleepover a guys house, but I really want to an have been invited to do so. So, I was thinking about saying I was sleeping at a friends, but in reality just going to his. Has anyone done this before? Thoughts. Don't tell me it's wrong and lecture me because I know it is. But I want to do this.