Gangbangs & Trains

I am not sure if this is the right category to post this topic under but if it isn't just let me know.

I have been fantasizing about being the focus of a train or gangbang both on its own as well as with CNC roleplay. While this is a more distant dream for me I wanted to ask for advice now so that I may use it to refine my pursuit. What are the best ways to do this for both safety and fun? Is it advisable to start smaller such as with a threesome? Would a play party be a good space to explore this or would this sort of play be frowned on at such functions? In a LTR are doms a case by case basis or do they tend to lean more one way or the other in terms of putting a sub in this position?