Swagging, the motion of which you do sexual actions. Swagging while dancing of doggy styling/dry humping a girl from the back in a rhythmic motion. Swagging by yourself is the motion of which a guy masturbates, in this he preforms in a rhythmic motion also.
swagging: the cocky behavior of someone who is riding high with self-confidence - especially as it spills into wild and crazy sex.
My boyfriend was riding so high after dinner with the boss that as soon as the boss left, he grabbed me and kissed me like that famous V-J Day kiss. He was swagging from the bar to the dance floor all night long. It was the best sex of my life.