Do I deserve punishment? What should I expect while getting apanked?

I am 18 and my bf is 20. Recently, I've been super sassy, rude, lying and hiding stuff from my bf. He cought me 3 times and he forced me to guve him a blow job as a punishment once, 2nd time was sleeping naked on the floor and 3rd was having harsh forced sex with him. We love eachother but I am so rude. I want to improve but its hard and he said he will do anything he can to help me. He warned me that he will spank my bottom fucking hard for hours if I lied or did anything bad again. I have never got spanking in my life. I dont know what to expect and how that works.does spanking hurts? Also, if you were my bf what would you do to me? Can someone explain how spanking works and what should I expect? How would you deal with me? Also, I had a sex with his friend and he locked me in dark room for a day but he might burst out of anger anytime... I am scared.Last night, we were supposed to have a sex together but I said I am tured and I lied and later he found me mastubrating and he said Get ready for tomorrow... what should I do?? How is it gonna be ? What would you do with my type of girl?