1. Refers to the male bicepts
usually in an attempt to show them off to the 'lady types'
2. Can also be a
metaphor for one's ego and current state of
adrenaline or pumped-ness.
(Saying to the lady-folk or man-folk if you roll
like that) "
Check out these manguns, careful now."
(Saying to someone making you look bad) "Quit steppin
all over my manguns."