How do I apologize to my boyfriends mom and what to say please help)?

So my boyfriends mom, found out he sneaked out just to see me and we spent like the night together. When he came home his mom found his hickey. And she found out about him sneaking out coming to my house and me giving him a hickey. She wants to talk to my mother, but I’m trying to convince her not too. And she wants to talk to me and my boyfriend. How should I talk to her and what should I say? Please help.
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Also I’ve never met her this is my first time meeting her.
How do I apologize to my boyfriends mom and what to say please help)?
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