When one acts by slapping their chest in an odd formality, whilst letting out a disgruntled moan of excitment.
ie; "ugggh!" (Moan).
Typically used when something exciting happens.
1.) I was made fun of at school today for chest tapping after we watched a documentary on the Cival War.
2.) Last night the drug store ran out of chest tap lubrication so I had to by the expensive brand at Family Dollar