khaire haru consider middle finger a little offensive (if you want to call it that) coz it is the biggest and longest finger in your hand and so, when self-masturbating, females use that finger most of the times. hence, the 'up finger' sign sort of symbolizes intention/incident/whatever you want to think about sexual intercourse...
tara, byapak use huda huda arthako anartha  huna gayo...tyasaile, middle finger ali naramro maaniyeko!

aru ta kehi kaaran nai huna sakdaina ni!

sorry, if that was offensive to anyone...comments welcome