My 5 year old staffy sleeps in my bed, and from time to time I will wake up and were he is, is wet?  It is wee as I smelt it to make sure.  He was sleeping on his back last night and I went to stroke is belly and it was wet too.  I let him out on a regular basis and right before we go to bed.  Is this common? or do you think there might be a health reason for it? 

Regards
Sheli

You need to see a vet.  He may have a urine infection.  If you take a sample with you to the vets they will be able to determine if he needs antibiotics or if there is any other cause for this.