Every couple of months, my 8 yr old will complain of the tip of his penis stinging. it only lasts a few minutes and tests for urinary infections are neg.?

See below: Circumcised males very rarely get urinary tract infections. His symptoms are most likely due to irritation.

Likely harmless: Am frequently consulted about this. Many boys develop a kind of mucus scab which closes urethral opening, this stings slightly when they begin to urinate when flow opens the stuck opening. Other causes can be rough underwear, laundry detergent. Occasionally due to so called "lacuna magna" which is a small diverticulum toward end of urethra. This is best managed by an experienced pedi. Urologist.