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Believe it or not, there is no absolute standard idea of what Swinging is. That's why Swingers have rules and their own sort of lingo to define each couple's boundaries. Two of these terms are "Soft Swap" and "Full Swap". Even with these terms, there can be some confusion because they can mean different things to different people. While there is a general idea of what is considered Soft Swap & what is considered Full Swap, it's up to you as a Swinger to find out what defines the play style of your potential play partners.
In Soft Swap, oral sex is generally considered as good but full genital penetration is not. This may not be the case for everyone though. To some people, Soft Swap may mean kissing only or touching only with no oral or genital penetration at all. That's why it's important to ask people their rules and not just ask if they are Full or Soft Swap. Most of the time, Soft Swap is like foreplay, and ends with same room sex with your own partner.
Full Swap can be an even broader definition. To Wifey & me, our definition of Full Swap Swinging is "Swapped partners, same room sex only, oral and full penetration WITH CONDOM are good and encouraged. No anal." But that's not the way it is for everyone. We have Full Swap friends that only play in separate rooms. To some couples, anal sex is also considered part of the Swinging repertoire. To others, condoms are optional. Most Full Swap couples would not consider sex without condoms or anal as part of the usual Full Swap experience, but playing in separate rooms is common.
Separate rooms can mean anything from playing in separate rooms at the same time in the same place to full on one partner is out playing on a Hall Pass (permission from one's partner to go off and have sex alone with someone else) while the other is someplace else. Same room (Wifey & I are same room only Swingers) is pretty self-explanatory. We play same-room only and we prefer to be able to see each other. Wifey and I enjoy watching each other in action; plus we are there for each other to make sure the other couple or single doesn't "accidentally" break any rules.
Anal sex is not uncommon, but still it is generally understood that unless stated ahead of time in their rules, anal sex is off the menu for many Swingers.
So, for all practical purposes, the broad definition of Soft Swap is "Swapping partners without penetration except oral sex." The broad definition of Full Swap is "Penetration between Swapped partners is expected." With any Swinging though, Soft or Full Swap, it's best to go over the rules before play. You certainly don't want to find out mid-play that anal is part of the menu: Surprise buttsex!