This is almost what I do to "comfort" access my trunk:
1. Stand one foot away from the trunk.
2. You should not be dead center, instead Make sure your right foot is dead center, which means you are about 12" or so to the left from the center.
3. Stand in a military attention position for 2 seconds. Take a deep breath.
4. Start moving your right foot forward at about 2.5 mph till at least 80% of you foot is vertically invisible hidden by the trunk as seen from top. Since you will be standing about a foot behind the car, take precautions to avoid parallax errors in you judgement for determining the 80%.
5. Retract your foot bringing you back to attention position "as soon as" your foot covered the 80% mark in step 4. Retraction velocity should be 2.5 mph.
6. Wait for about a second and you should notice the tail lights blink and the trunk opens. Congratulations!! If not, repeat steps 1-6 or try variation 1.
Variation 1: In case you are with friends or if people are watching you and you want to save yourself embarrassment in case of failure try this variation to the above steps:
1. In step 3 above instead of standing in attention, stand with your left hand inside your left pant pocket, holding your BMW key, finger on the trunk open button.
2. Continue with steps 4-6.
3. If step 6 fails, long press the trunk open button without causing apparent external movement of your hand inside your pocket.
4. The trunk will open.
Variation to variation 1:
In case you got your car reprogrammed for ASS last user mode, you could perhaps also use the panic button instead of the trunk open button on your key fob