RT diaper position / laying on stomach - different feelings

Are the differences only in exposing, may be situations (from nurse/doctor/parents)? Or did you recognite different feelings in your bottom too (during procedure)?

I've only taken my RT during anal play, and for that purpose, I can say I felt no difference in the sensations directly in my bottom, no matter what position I inserted the thermometer in. Psychologically, I've always found the laying-on-stomach position far more arousing and erotic than the diaper position, although many believe the opposite.