which one is which???

so dominic and i flew out to san diego to spend thanksgiving week with my family as we welcomed jake home from iraq...he got to meet my sister charity and her husband aaron for the first time...
we were all hanging out in the living room watching tv and charity walked up behind dominic and starting rubbing his back...she said "heeeellllooooo"...it wasn't until my step-mom sharon said "you do know who you're rubbing right?"
charity freaked out...she got all embarrassed and said she couldn't tell the difference from behind...here is her photo proving her point...
dominic is the one on the left...aaron on the right...