This design was notorious for slipping either forward or back of the intended position.

She swung her leg over the branch and slipped forward.

Then he slipped forward to stand by the nearer line of stones.

The woman slipped forward and fingered several of the sheets.

She slipped forward out of the chair and hit the floor in a dead faint.

Then she slipped forward and fell on the door.

Without waiting for an answer, the page slipped forward, and filled each of the fragile cups.

The sound came again and Kate slipped forward through the trees.

The star slipped forward - there was an almost imperceptible movement of its side points.

He heard voices ahead, and slipped forward, close to the wall.