The act of 'accidentally' forgetting an article of clothing or object to give yourself a reason to come back to someone's place and fuck.
When Jeremy left his hat at her house, she was convinced that it was a sexcuse article. This was proven a fact when he asked to come over to collect his hat because he wanted a bootycall.
While visiting my parents, Jeff and I usually use the sexcuse of needing a gallon of milk from the grocery store. That gets us out of the house long enough for a quicky in the backseat of the car.
When you decide that you can skip going to the gym, because you had some sweaty, exhilirating sex, that you feel you've worked out hard enough, and have burned those calories just by banging
Trent: "Morning babe, want to go work outwith me?"
Abby: "How about you just work me out and do some sexercise instead?"