Kira, my Staffie, every evening, about 7-9pm, goes into a licking rampage, and will sit on my lap and lick my hand for approx 30-60 minutes, and if my hand isn't available, she'll lick any part of me or my fiancee... it isn't like we have food on us, she just likes to lick...she'll go get some water then come back and lick us some more... it lasts some nights for over 2 hrs... last night we had her get off my lap, and she proceeded to lick the carpet for a while, then found my hand and started again....
I don't think it's anything to worry about, and it's funny sometimes, but we just wanted to make sure it's okay..
A side note, we took her to the vet for this first time since we adopted her, and she actually loved the entire trip, she was wagging her tail, giving her pitbullish smile, and just loving life...