Since my feet are soft and very ticklish, a duck feather will drive me insane in a very short time. This is especially true when my bf expertly manueuvers the feather in between my toes. As far as the toothbrush setting goes, my bf has only used the Sonicare on me a couple of times and it was devastating. I believe the bristles may have been soft, but I was so hysterical with laughing pleasure, I cannot recall. Considering how soft and ticklish my feet are, a softer bristle would probably do the trick. We might do some tickling this weekend, so, if I can gather the courage to withstand another Sonicare experience, maybe we can experiment! TICKLE,TICKLE,TICKLE...