When we throw a house party with 6-8 couples,we always put it on the invite. Party starts at 8:00 (drinks,food and socializing),clothes come off at 10:00. My wife and I always pick a partner to start the ball rolling,we have had 2 hours to entice our choice and things have always worked from their. Once the hosts and their choice is naked, then there partner usually follows and pretty soon we have a nice group swing going. we have had over 8 parties started in this manner and have 100% success.