In Rugby what constitutes a bent arm penalty?

Question

When the referee calls a penalty they are almost always straight arm penalties. but I am aware that ocassionally a less serious penalty occurs in which the referee keeps his arm bent. what could cause a ref to give a bent arm as opposed to a straight arm. and what is the difference in the penalty itself (i.e. is there still a ten yard retreat by the offenders, what happens about kicking into touch.......)

Answer 1

When the referee blows with a bent arm it is a free kick.  Very often this will be a scrummaging offence ie not putting the ball in quick enough or not binding properly