Eureka! I have solved this problem.
Disconnect your Senseo from the power. Take it to the sink. Hold it upside down and put hot water in the coffee outled. In less than 30 seconds the senseo will open.
The problem with Senseo is that - especially with coffee holders for 2 cups and chocolate - after making the coffee, the pod holder and the pod cool down. This creates an underpressure, that prevents you opening the Senseo. Hot water will increase the pressure and then you can open the senseo very soon.
This solution was found in despair after struggling with all the complex tool involving (knives, pumps, etc.)
Let me know if it works for you
Hans Beers ([email protected]