I think 2 hours is too long to try WILD. Especially for a nap.

If I can't do it within an hour I figure it isn't going to happen. If you insist on trying it during a nap make sure you are good and tired. The more tired you are the faster your body will fall asleep.

Otherwise try what Mes T suggested. That's the usual method people use to attemtp WILD when first starting out.

And try to ignore those sensations. I know it's hard but keep at it. You'll get it if you keep practicing.