As you may or may not be aware, the students of Xavier's are each assigned a student mentor upon entry into the school.
The mentors are members of the faculty, usually X-Men, and will often tutor them in combat to supplement their usual Danger Room sessions. They also serve as study buddies, helping them catch up in areas where they might be struggling, and aid students who may have personal issues such as bullying.
Put simply, the mentors are there to be instructors, teachers and counselors all rolled into one. All of them will involve themselves in their roles to different extents.
To assign yourself a mentor, PM the X-Man of your choice or one of the staff. X-Men may opt out of this if they feel their workload is too large, or temporarily stop taking on new students if their roster gets too much for them to handle.