Should have - regret not having done something. I should have married my college boyfriend, we were so compatible. Could have - had the opportunity, but didn't take it. I could have married him, but we were not compatible.

You tube or Skype with a native speaker

It means I am beaten; I have lost or I give up.

casual conversation

Can I use this expression when I fail to pay? Is it common? ; Carlos and I are up to our assess in bills.
e.g
A: Carlos and I are up to our ears in bills. 카를로스와 나는 청구서에 치여요.
B : You might want to think about looking for a job. 그럼 직업을 구해 보는게 좋을 겁니다.

Sometimes when Korean moms call their children, can I use it like this; Get your little fannies inside! Is it normal expression? Yes or you can say "Little butts" or "behinds" instead of fannies.
When the kids are punished, can I say like this: take your lumps.
e.g
Mom : Get your little fannies inside! 얼른 집에 들어와!
Uncle : Who you hiding from? 누굴 피해 있는 거야?
You know ?what I say? Go on home, take your lumps. 무슨말인지 알지? 집에가서 떳떳하게 벌을 받으렴.
Kids: We don’t want to get spanked. 엉덩이 맞기 싫어요.

Movie again.

Very early this morning, my friend and I watched movies in hongdae.
We made a plans to watch two movies one after another because we preferred to watch two different movies. xD
So I got up really early, went hongdae, watched 7번방의 선물&몬스터호텔
(present of room.7&Hotel Transylvania)
The 1st one, 7번방의 선물 was really funny but so sad.
We both cried. ㅠ_ㅠ
Because of this we had really heavy and sleepy eyes all day.
After watching moviews we had TACO at lunch in TACOBELL, and went to cafe to talk, then came home.

Thanks in advance! I've just started to write diary in english on my note book(not italki note i mean) so I think I'll write many note from now on so thanks you guys in advance for correcting me.