Google thinks that berceurse is bear suz, similar to suds, so that's no help. Monique's link is nice, but it's only talking about the long u umlaut. The long umlaut has ee in the back, but the short one has short i in the back.

Not every umlaut calls for rounded (or pursed) lips. Traueme is pronounced troy-meh. And Haendel (the composer) is Hendel. Spaet, the word for late, is schpate.

To finish the story, the long o umlaut has long ay in the back, and the short o umlaut has short e in the back. That's all of them, I think.

In Milwaukee, where I grew up, if you were named Schroeder, you were called Schrayder, because people remembered that long a in the back of the mouth. Also Koenig was Kay-nig.