****HOW DO I CONVINCE MY MOM TO HAVE A SLEEPOVER WITH..**?

okay. im 16. my mom is strict in some departments. i have a few piercings and shed maybe allow a tattoo, so she is not that strict. but when it comes to my boyfriend she kinda is. she lets me over his house until 1030 every other day, as long as he comes to my house some days. hes not allowed in my room however:/ i wanted to ask her..... if i could have him sleep at my house. when we hang out its always in my living room near the steps. its not a closed off room so whenever she comes down she could see us so i dont think that is a concern... does anyone have any tips or stories.? my boyfriend is 18 and im 16 she ok'd it cause hes a reallllly nice, good person and she knows im extremely safe with him, and she never feels that way with anyone else so she likes him alot.. thanks alot for whoever tries to help or sends their stories.