Scholars have offered numerous approaches and best practices for mentoring faculty, many of which have provided valuable insight into the complex nature of the mentoring process. Yet, little attention has been paid to how faculty mentoring practices can influence a mentee's intrinsic motivation. Through a series of 15 interviews with faculty members from mathematics, engineering, and life science, coupled with the use of self-determination theory, the author demonstrates how disciplinary backgrounds influence their needs for autonomy, competency, and connectedness, which effects their intrinsic motivation to engage in scholarly work. The author highlights three themes that speak to the notion of "non-intrusive" mentoring practices that can help foster and sustain motivation, and argues that future research is needed to shed more light on how disciplinary cultures influence mentoring.