A frustrated wife buys a pair of crotch-less panties 

 in an attempt to spice up her dead sex-life.
 She puts them on, together with a short skirt 

 and sits on the sofa opposite her husband.

 At strategic moments, she uncrosses her legs ...  

 enough times till her husband says... 

 "Are you wearing crotch less panties?"  
   "Y-e-s," 

 she answers with a seductive smile.

 "Thank God for that... 

  I thought you were sitting on the cat. 
 
   He never heard the gunshot.