First see definition of "Bunker."
A “bunker” is a hazard consisting of a prepared area of ground, often a hollow, from which turf or soil has been removed and replaced with sand or the like.
Grass-covered ground bordering or within a bunker, including a stacked turf face (whether grass-covered or earthen), is not part of the bunker. A wall or lip of the bunker not covered with grass is part of the bunker. The margin of a bunker extends vertically downwards, but not upwards.
A ball is in a bunker when it lies in or any part of it touches the bunker.
Next, look at "Embedded Ball." Unless there is a Local Rule allowing for relief "Through the Green" for Embedded Ball, then no relief is available as Stacked Turf would not be "closely-mown."
25-2. EMBEDDED BALL
A ball embedded in its own pitch-mark in the ground in any closely-mown area through the green may be lifted, cleaned and dropped, without penalty, as near as possible to the spot where it lay but not nearer the hole. the ball when dropped must first strike a part of the course through the green. “closely-mown area” means any area of the course, including paths through the rough, cut to fairway height or less.
Ball Embedded in Grass Bank or Face of Bunker
Q. Are grass banks or faces of bunkers considered to be “closely mown areas” under Rule 25-2 (Embedded Ball) and may relief be taken from them under that Rule?
A. No, not unless they are cut to fairway height or less.
Finally your answer is "Play it as it lies" or "Declare the Ball Unplayable."
The player may deem his ball unplayable at any place on the course, except when the ball is in a water hazard. The player is the sole judge as to whether his ball is unplayable.
If the player deems his ball to be unplayable, he must, under penalty of one stroke:
a. Proceed under the stroke and distance provision of Rule27-1 by playing a ball as nearly as possible at the spot from which the original ball was last played (see Rule 20-5); or
b. drop a ball behind the point where the ball lay, keeping that point directly between the hole and the spot on which the ball is dropped, with no limit to how far behind that point the ball may be dropped; or
c. drop a ball within two club-lengths of the spot where the ball lay, but not nearer the hole.
If the unplayable ball is in a bunker, the player may proceed under clause a, b or c. If he elects to proceed under clause b or c, a ball must be dropped in the bunker. (If the ball is plugged in a stacked turf face of the bunker it is not in the bunker, so you do not have to drop it in the bunker) When proceeding under this Rule, the player may lift and clean his ball or substitute a ball.
I LOVE THE RULES!