Start by putting a can or jar on the ground in front of you. Then, put one leg behind you with your toes touching the floor.
First, keep the standing leg straight with a slight knee bend, lean over and touch the product, and then return to standing up straight. Practice this a few times and you'll discover you are stretching the hamstring or back of the standing leg while strengthening that same glute as you come up.
Make sure you come all the way back up to a vertical standing position.
Once you've mastered bird-feeding with the back leg stable, allow it to lift up when you go down to touch the can. This adds a balance challenge to your move, really working core stabilizing muscles along with increasing the work load on that standing leg and bun.
Finally, if you want to work harder, take the can or jar with you as you bob up and down. This provides added weight to the move, providing a bit more calorie-burning effort.