LS friendly treehouse - need suggestions for mild bondage items.

We have a double 2 X 6 beam across the living area. Is there a way to add a large X that we have seen in some pics. This "X" will have to be removed very easily.

We do like the idea of the eye bolt in the ceiling, thanks.

We have a black iron hanging candleabra over our bed. It is hanging from a hefty I-hook that is screwed directly into a rafter and will support a sex swing. If we want to use the swing we just take down the candleabra and hang the swing from it. You can use the I-hook for other things as well (i.e. rope play).

We are newbies looking for light bondage items to add to our treehouse that can be removed easily should family or friends show up. It's about 370 sq ft with a sunken queen size bed in loft & full size downstairs. Any suggestions will be much appreciated.