(Pronunciation; Gro-obe)
Much like groping, grobing is the alternative to when referring to groping within the ass, such as anal probing, but put within a sexual setting. (Grope + Probe)
The process of reaching down into your pants at socially vulnerable times to properly arrange the penis and / or scrotum, for males, or the labia, for women, to accommodate your current physical positioning.
He: "Sorry dudes, ya might wanna look away - I gotta junk dive and set my sac back in place."
She: "Sorry girls, look away, the lips are loose - I gotta go junk diving."