I start to ease back on the yoke fractionaly after pulling the 2 stages of flap in, and I only pull it enough to break the nose down motion. During the take of run down the runway I hold the yoke as neutral as possible.
Holding the yoke back on a rough bumpy strip is not a great idea, once the speed starts building she will start bouncing about like a looney. For the average grass strip you wont notice it to much.