The definition of intersectional is: "the interconnected nature of social categorizations such as race, class, and gender as they apply to a given individual or group, regarded as creating overlapping and interdependent systems of discrimination or disadvantage."
While sex-positive is described as: "having or promoting an open, tolerant, or progressive attitude towards sex and sexuality."
To me, it's about celebrating diverse sexual expressions, practices, and identities.

Understanding that our experiences are individual and multifaceted and to be aware of our biases, views and backgrounds. 
Intersectional and sex-positivity, need to be one and the same. We can't and shouldn't have one without the other. 
Intersectionality is wildly omitted from much of psychology and psychiatry and there is a long way to go.