I have been using these enemas for years. The bottle were changed a few years back (can't remember when) but they are hell to squeeze now.
If your medication are covered by insurance I would recommend that you squeeze one down the drain so you can see how they work. That way it will be easier to do so when you are laying down on your right side with your hand behind you.
Actually, I always squeeze a little bit of liquid out before I inserte it. There is a bit of lubricant in the cannula and it kind of makes it very difficult to get the liquid out if you don't squeeze it out before.
I just don't get why the lubricant is in the cannula and why these bottles are so hard to squeeze? It obvious the ones making those are not users.