I think the first person is correct. It's about lusting after someone. And I think it's the singer of the song who's being lusted after. When she says "be my angel," she's accepting his invitation. She doesn't want the man to think his efforts are in vain; she doesn't want him to think it's useless or to forget it. She has an effect on him and makes him do things he otherwise wouldn't. Maybe she's been hurt in the past, and that's why she asks him to be kind to her.
I think the first person is correct. It's about lusting after someone. And I think it's the singer of the song who's being lusted after. When she says "be my angel," she's accepting his invitation. She doesn't want the man to think his efforts are in vain; she doesn't want him to think it's useless or to forget it. She has an effect on him and makes him do things he otherwise wouldn't. Maybe she's been hurt in the past, and that's why she asks him to be kind to her.