How to safely and effectivly attach and change a needle?

[marsbar2k5]

So my first pin by myself this morning, feel like a complete tard.
The pin itself was painless, but went through 4 needles!
The needles im using are an 18 guage and 25 guage, the 18 to draw the solution and the 25 to pin.
I could not for the life of me get the plastic protector of the top of the needle, I pull until it suddenly jerks out and managed to make 2 small cuts in my hand with 2 different needles. Once whilst attaching the 18 then once whilst changing to a 25! I didn't want to risk it so instantly disposed of them, needless to say its a waste of a needle and I look like a tard.
I disinfected and put a plaster over the cuts, the pin itself was completely painless with no pip and almost no blood (researched a fair bit about injecting, but not needles!)
Was thinking about getting an amp snapper, but no idea how they work.
Any guides or advice?

[Lunk1]

Are you screwing them on the barrel befor removing the pin cover?

[Live for the PUMP]

lol dude. Pins screw off, not pull. Oh man.

[panntastic]

lol dude. Pins screw off, not pull. Oh man.

In England the Bd ones just push on and off no screwing

[marsbar2k5]

Are you screwing them on the barrel befor removing the pin cover?

They don't screw on but I do place them on the barrel first, seems as if its a snaping sort of motion to remove the guard?

[Lunk1]

They don't screw on but I do place them on the barrel first, seems as if its a snaping sort of motion to remove the guard?

Yeah...I get the screw on (luer lock) pins. This is a better system imo. Just twist and pull a bit at the same time.

[Live for the PUMP]

In England the Bd ones just push on and off no screwing

Gotcha