How do I get her to stop?

Since we found out we were pregnant my MIL puts her face right at the bottom of my stomach talks, kisses and rubs my belly. It doesn't matter if I'm standing or sitting. I understand she is excited about her new grandbaby but it's really awkward and uncomfortable when her face is almost in my crotch! How do I get her to stop with out hurting her feelings? I'm 17w 5d. And she has been doing this since we were 3 weeks and I have just been dealing with it but not sure how much longer I can do that...