not wet enough!

So I was having sex with my boyfriend and I am starting to notice that I get extremely dry down there! And I don't want to be! I want to keep going but for some reason I get so dry it's ridiculous. He's gave me oral, he's played a little, we even took it slow to "be in the moment" and I'm so into it and then I'm just as dry as the desert and it kills it for me. Any suggestions on what I can do to stop being so dry? Please and thank you!