soft swinging is basically anything but full swap (you don't have intercourse with someone other than your partner). As for what it is within that, that depends on the person using the term. It could just mean same-room sex (watching another couple have sex as you have sex with your partner), or it could mean anything but.. meaning that you swap for foreplay and oral sex but when it comes time to do the deed you do that with YOUR partner.
Julie
http://www.swingersboard.com