Doing my usual news browsing while having a morning coffee and trying to wake up, I came across a video of Rory Cellan Jones making a clown of himself doing something I'd expect a 5 year old to do with ease. He was evaluating the benefits of the "new idea" that is the milk bag, as an alternative to glass bottles and plastic pints which are the norm in the UK. First off, Rory, I'm not sure what kind of bizarre contraption you bought but if you'd bought a straightforward milk bag jug, like the one on your right here, you would have been done in about 3 seconds flat.
Step 1: Put milk bag (which in my lifetime, I've rarely seen leaking) into the jug. Step 2: Snip the corner of the bag by holding the very corner and using scissors or these tiny fridge-magnet bag clippers. Step 3: Pour the milk into the glass. Step 4: Drink milk.
It's far from new, it's been the most common way to buy milk in Canada for my entire 26 years of life. The milk comes in a bag of 3x 1.3 liters transparent bags, and the best part is that these milk bags make the sturdiest lunch snack bags ever afterwards and create a hell of a lot less waste than bottles or plastic containers.