playing out a fantasy

so, recently talking with my wife, she told me that she had a group sex fantasy that she'd been thinking about for a long time. neither of us want to bring other people into the bedroom, we dont like sharing. i was wondering if anyone had ideas on a good way to act this out, as close as we can with just me and her. i know they sell strap-ons for guys on here, to get the whole dp thing, but is there anything else we could try out?