Intimate Predicament

Being long distance, my boy and I try to make the best of our morning before he goes to class. This morning was flirty, me being partially exposed from wearing just an open flannel and girl boxers. I'd like to help progress our intimacy, though showing my lady bits- I'm not exactly sure I'm comfortable with. I've never been that intimate with anyone.
I hate that we get to a certain point of flirting to where I kind of hesitate, and he feels like he has to give up with trying to progress to more. I'm not sure if it's my self esteem with being a larger woman or if it's just because I'm worried he'd judge my fully naked body.
In the very least, we were able to joke around and make light of the situation as we both got ready for our day. I need some advice on getting comfortable with that intimacy