He tries, he really does. Castiel's fingers shake, but his body just locks up. He wants to be rid of the plug right now, but it's just not happening, he just locks up entirely, tenses. The angle is uncomfortable even with a raised leg, and Castiel bites into his fist to keep from crying out.

It hurts, just the attempt to remove it.

And as the minutes tick by, he realizes he has to ask for help.

"Sam... I can't... I don't think..." Castiel pauses. Just breathes for a moment. Then looks at Sam's back, despairing. "Sam, it hurts..."