BDSM - Bondage/Discipline, Dominance/submission, Sadism/masochism
Pansexual to me is someone who is attracted to the person regardless of where they identify in terms of gender.
Master/slave is a dynamic of Dominance & submission that takes it to a deeper level. www.fetlife.com
is a good resource for information on that - but be warned, its rather graphic if you're offended easily.