Sexuality is a major part of mental health but has been poorly evaluated in psychotherapeutic and psychiatric settings. This scoping review outlines the dominant guidelines and optimal procedures for the clinical management and discussion of sexuality with adult patient. It reveals main obstacles to successful integration of this dimension, including poor training, uncertainties in existing guidelines, clinicians’ reluctance, and deep-seated taboos in institutions contexts. Effective solutions include intentional integration of sexuality into assessments, preparatory and open discussion, sex-positive and inclusive communication styles, and flexible clinical models. The nine studies included yield strong evidence in favor of a structured method following the bio-psycho-social model of management. The thematic synthesis outlines key elements required for successful facilitation of effective clinical interactions and provides a basis for constructing useful tools to aid mental health professionals in sexual health issues in respectful, inclusive, and constructive ways in adult mental health services.