During a three way, (two women and one man), The man and one of the women in a wall mount position "sliding rod". Meanwhile the other woman, positioned behind the man, would be giving oral pleasure to his anus. At this time it may be appropriate to give finger stimulation to the man's taint, not required though, it may just seem curtious. Rusty= anal pleasure; Slider= act of intercoures.
Last night I was wall banging Betty, when all of a sudden, Sue, her roomate came from behind and vigorously assualted my asshole with her tongue. Dude, Rusty Sliders kick ass.