i think thats indians or tamils who wipe their backsides with bare hands.
never heard that associated with muslims
well here is a an extract from The Book of Taharah (cleanliness) A part from 'Nur al Idaah' (apparently an authoritative islamic text)
"4.7 Method of performing istinja’: if one’s testicles are hanging one should wipe with the first stone from the front to the back and with the second from the back to the front and with the third from the front to the back [for fear of defiling one’s testicles, Mf: p.89]. If the testicles are not hanging, then one should start from the back. A female should start from the front to the back for the fear of defiling her vagina.
4.8
Thereafter, one should wash the hand and using water wipe the soiled area with the inner side of one, two, or even three fingers if needed. A male will raise his middle finger over the rest when commencing the istinja’ [then after washing slightly, Mf: p.90] he will raise the ring finger [Z: and if need be then the small finger and then the index finger, Mf: p.90]. One should not suffice upon the use of one finger. A female should raise her ring and middle finger simultaneously from the outset for
fear of being sexually aroused.
4.9 The utmost should be done in cleansing oneself until the foul smell has been eliminated, whilst thoroughly relaxing one’s buttocks [Z: so as to clean what is in the passage to the best of one’s ability, Mf: p.91], unless fasting. Upon completion one should wash the hand again. If fasting one should wipe oneself before standing. "