https://www.eccie.net/showthread.php?t=2368276 has some good info, Lyssandra.
Mokoa is correct that "duos" alludes to P4P, but here is a little more info that you might find helpful.
• Often, our Upgraded Female Accounts offer "threesome" appointments, i.e., working together with another lady in the community, however she MUST also have an Eccie Upgraded Female Account. You may not use the term “doubles” anymore. Instead say that you have a friend or partner who can join you. In those situations, we do allow you to mention this availability and we do allow you to mention your partner by name, even if she has also posted a Weekly Update for that week and mentioned you as a partner as well. This situation in particular, however, will be monitored closely to prevent abuse or circumvention of our guidelines. Please limit this to simply mentioning your partner's name, and the details of the availability. Two Weekly Updates in the same week that are "centered around” your threesome availability may be considered excessive, and limitations put in place.