I have a friend who is single and pregnant and I don't want to out my pregnancy fetish but I also want to see her growing belly! She said she doesn't know if she wants to show it. How do I subtly encourage her to show off her gorgeous pregnant belly??

I don't believe you can. If she's already expressed discomfort with the idea, any further persistence on your part is going to raise red flags -- because why would a "normal" person be so insistent?

If you value your friendship with her, you're going to have to leave that alone. If you don't really care, sure, go ahead and risk it.

Just hope she changes her mind down the road, otherwise if she's hesitant on showing off her stomach then it's not worth trying to go any further. Especially if you don't want her to find out about your fetish.

Given what you've said about her hesitancy to do it, if you want to see it you have to approach it in the most non-threatening way possible. You could mention how you saw some belly feature - stretch marks (or no), linea negra, innie/outie belly button, whatever - on someone you know (sister, cousin, imaginary girl) and that it was ___________ (cool, weird, BS something here). It's a passive-aggressive way of suggesting she show you without actually suggesting it. If she takes the bait and shows you, great; if not, you could casually ask her if she has the same thing (but don't ask to see it); if she still doesn't take the bait, it ain't happening.

Keep in mind that this will only work if she's not shy about talking about her belly. If she is, just forget it.