My cigarette lighter would NOT pop or stay in and my other 12v item would NOT stay in so.. HERE IS MY FIX!!
Always use the proper tools
1. Warm it up if possible
2. Spray it with penetrant
3. Hammer it, spray it again(let it soak if you have time)
4. Tighten it a little bit
5. Loosen it and watch the other end if you can.
6.Work it back and forth if its stubborn.