I was out with my mother in law and one of her girlfriends when we saw this woman spanking her young son on his bare behind for acting up. The kid began crying after just one smack. I mentioned how quickly he began crying. My mother in law told me it depends how hard the smack was and then asks me if I was ever spanked and how many it took me to cry. I told her I wasn't spanked much but could take more than just one. She then asks how many I think I could take now. I told her easily about 20 or more. She then challenges me to put my money where my mouth is. I was surprised by her challenge and asked if she was serious. She said she would spank me 25 times on my bare behind. She was serious and the bet was that I couldn't cry or beg her to stop before she was done. There was no real prize for the winner other than seeing if I could handle her spanking me 25 times. I agreed to the challenge and a few rules were agreed upon. It was going to be on my bare ass, she could use an item like a belt or paddle if she wanted and if I moved or put my hands on my ass to stop the spank 5 additional spanks would be added to the total required spanks.

Once back at my mother in laws place she had me lay across he lap and pull the back side of my jean down exposing my ass. Both her and her friend where seeing my bare ass, they had never seem me naked in any way, and I didn't really think about how my wife would feel if she knew this but the challenge was to continue. She began spanking me and my shirt kept dropping down to partial cover my ass. She asked me to remove it which I did. She had only done 3 spanks at this point and then did 3 quick spanks. They stung and I stupidly put my hand over my ass which added 5 additional spanks to the total. Her and her friend laughed at me and told me there was only 24 to go now. She took the belt from my jeans and began using it on me. It was 10 hits later and my ass was already very sore and I began to think I wasn't going to be able to complete it. I began to feel a lot of pain but was not crying. I didn't realize it until after it had happened but my mother in law had slipped my pants and underwear right off me. I was only wearing socks and when I mentioned it she took them off and told me I was now wearing nothing and chuckled. She quickly hit me twice and my hand went to cover my ass to stop it which added to the spanking total once again. She was beginning to realize that anytime she spanked me quickly I would try to cover my ass and have additional spanks added to my total required. She also knew how to spank me to have squirm more. I didn't think much about this at first but I soon realized when I squirmed I would sometimes roll sideways and move my legs apart which was exposing my cock and balls to them. I must have already taken about 30 spanks by this point but with all the additional penalty ones added had about 30 remaining. My mother in law wanted to change the way I was being spanked and told me to stand up and lean up against the wall. I told her I would be too exposed and would stay on her lap. She then did one really hard fast hit that was extremely painful. She then asked me if I wanted more like this or if I wanted to lean up against the wall.

I ended up leaning up against the wall. There I was naked with my cock and balls hanging in front of them. My mother in law came up behind me and put one hand on my stomach as she spanked me with her other one. The hand on my stomach slipped down and was now gripping my cock. Her friend approached and put her hand there too. They made comments and then made me an offer. They said they would trade all my remaining spanks if I would spank the monkey for them. My response was that I was married to her daughter and couldn't. They promised not to tell and asked how many more smacks my ass could take from them. I didn't know how many more I could take so I began to do what they asked. There I was with my cock in my hand and my mother in law and her friend watching me. No one, including my wife, had ever seen me masturbate and there I was doing it in front of these two.

Finally it was all over. That day I exposed myself more than I ever had and also it was in front of my mother in law. She did keep her promise not to tell my wife but does occasionally make comments to me when we are alone and has even taken it upon herself to take peeks and touch me whenever she pleases. Some peeks have been with her pulling my pants down to my ankles and getting me aroused.