Maybe my sense of humour.
Though in fairness, you obviously did not include that in your preconceived "five senses".
So as an alternative, I might suggest my "common sense".
Of course, you do not even include that one in the so called "five".
I know that to be the case because I am blessed with a very discerning "extra sensory perception" and that particular one is indeed my favourite sense.
Touch. Simple skin on skin contact can be incredibly gratifying.
Hearing or sound.
Hearing :)