I'm no expert by any means but I'm guessing that you still have some pressure in those two lines (male side) that are on your FEL.
My green line on my FEL holds some pressure and I have trouble hooking it back into the tractor sometimes. What I do, and it's probably wrong, is take the male end and tap it on the side of the FEL. Not real hard but enough to push that male part in a little to let off some of the pressure. One tap usually does the trick.
A few warnings:
It will squirt out some hydraulic fluid so keep a rag handy. Wear safety glasses.
Wear leather gloves, especially the first time you do it. Those lines hold about 2500 PSI and you don't want it getting inside you.
Your hands shouldn't be near the end of the hose when doing this but wear gloves anyway. Don't even think about pushing in on it with your thumb, knee, palm, etc.
The FEL may move a tad when you let off some pressure so be prepared for it. Don't put your hands where they can be pinched.
.....but there probably is an easier way to do it.