Michael, here's an interesting study showing how male circumcision enhances sexual performance and satisfaction

"CONCLUSIONS: Adult circumcision does not adversely affect sexual function. The increase in the ejaculatory latency time can be considered an advantage rather than a complication."

This increase in "ejaculatory latency time" is due to What is Lost in Circumcision

"1. The frenar band of soft ridges--the single most pleasure producing zone on the male body. Loss of this densely innervated and reactive belt of tissue reduces the sensitivity of the remaining penis to about that of ordinary skin."