The redundant sex that results after several years of marriage. It is not necessarily bad, just boring. You know she likes "this" and she knows you like "that" so all you do is "this and that". There tends to be no deviation from the set pattern after several years and all foreplay disappears. Undress, lie down, hump (only 1-2 positions allowable), and done.
Me: "I wanted to 69 with the wife last night and get out the ropes but all I got was married sex."
Friend: "Bummer, man. That must have been boring!"
generally performed first thing in the morning before work starts and anyone is awake. sneak out to kitchen, turn lights on, start kettle boiling so as to make noise to act as the alibi proving you are in the kitchen, sneak very softly to the toilet an crank the shit outta yourself, sneak back out to kitchen then walk loudly back to toilet and piss loudly to give you a legitimate reason to be flushing toilet.
(alarm goes of) *beep beep beep*
(think to yourself) "hmmm....another piss fat. time for married sex"