Type of sex magic's brief function to begin with (7)
I believe the answer is:
tantric
'type of sex magic's brief function to begin with' is the definition.
I can't judge whether this definition defines the answer.
'brief function to begin with' is the wordplay.
'brief' becomes 'tric' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'function' becomes 'tan' (tangent, mathematical function).
'to begin with' says to put letters next to each other.
'tric' put after 'tan' is 'TANTRIC'.
Can you help me to learn more?
(Other definitions for tantric that I've seen before include "meditation?" , "of religious writings" , "referring to some teachings" , "Relating to Hindu mysticism" , "Coming from religious writing" .)