Dominance and submission is a set of behaviours, customs, and rituals involving the submission of one person to another in an erotic lifestyle.  Dominants take control in the relationship and submissives submit themselves to the control of their Dominant. These roles and relationships are entirely interchangeable in terms of gender identity and sexual orientation. 

All of these relationships are contingent on the mutual consent and satisfaction of both partners.  Although the role of submissive in particular may feel demeaning to someone peeking in from the outside, if an adult who is mentally capable of consent finds it most satisfying to service the needs of another, that is their own personal business.  Their choices may not be for you, but then, your life isn’t for them.

These roles and relationships involve an exchange of power, not a surrendering of power.  In the vast majority of cases, submission is considered something that must be earned  through respect and honesty.  The submissive really holds the power and if the dominant loses his/her trust just once, it's over.