hope this helps... a girl i knew used to get excited when talking & reading about gangbangs. she couldnt be involved in one where we live as she would always be seen in pubs & around town ever afterwards. her biggest fantasy was to sit & observe a rugby players changing room after a game. on her birthday i went with her to an open air rock concert in the midlands.we camped on the site & after packing up to go home we noticed a game of rugby going on at nearby playing field...WOW she said....can we go & watch them. so we did much to her delight...i got to talking to one of the substitute players waiting for a game & said quietly it was my friends birthday & her ultimate present would be to sit in the mens changing room after the game.he said he ,d have a word & told us to wait after the game. he ran back out afterwards & invited us both in. shelley my friend was in heaven as she watched several big strapping players changing & returning from the showers. it only took one player to stand in front of her & open the towel from around his waist.shelley sat mesmorised as she allowed his cock to brush across her face.it was soon in her mouth which signaled the others to gather keenly around her. her gangbang wish then ensued !
.try getting a big round table for everyone to sit at , Play Strip poker....or something more creative... .,,,an old drinking game called "I never" could be played like a strip game. someone says what they have done....who ever hasn't; has to remove some clothes!!! Not everyone is up for group sex, so just try to make everyone as comfortable as possible..... ...encourage letting people slip-away for a threesome, if they're not comfy being watched by too many people!
Maybe the last part, but you can't break the ice of a gangbang by saying 'okay lets get naked and have sex now' the strip poker/i never game would be a good way of getting things started, just minus the other room 3-sum part.