A wife buys a pair of crotchless knickers in an attempt to spice up a dead sex-life.
She puts them on, together with a short skirt and sits on the sofa opposite her husband.
At the odd moment she crosses her legs ... just enough times till her husband says, "Are you wearing crotchless knickers?"
"Yes," she answers, seductively.
"Thank goodness for that. I thought the stuffing was coming out of the sofa!"