parents and relationships

I love it when my boyfriend comes over for the weekend and we get to spend some quality time together, but, the thing that does make it a bit difficult is probably living with my parents during the scenario

Though I'm almost 25 (he's 28) my mom tends to check up on us every now and again and has a rule of leaving the door cracked which he respects and I do too. It makes things a bit hard to get intimate even when it's only making out and it's like we're on the edge of our seat type of ordeal. I love my mom, but at the same time, during certain situations I almost feel as though I'm still being checked up on like a kid though we're all adults.

My dad doesn't do it at all really it's just my mom when my sister and I were younger she made the rule of leaving the door cracked when there'a a guy in the room, but, now that we're both adults is it valid to still have that as a rule? I'd like to know ya'lls opinion because to me it feels like lack of trust and being monitord like a kid/teen would be in the situation

How could I have that conversation with her of feeling this way? It feels weird since I'm almost 25 having a conversation with my mom about monitoring, but, she's done it ever since I was a teenager with guys (which made more sense then than it does now) ;-;