Shy mom

I’ve lived with my mom since she divorced from my dad 10 years ago. She has always been very liberal in her parenting and so at 18 I was pretty much allowed to do whatever I pleased. Many of my friends would joke about getting my mom in bed, because of how young she looks. My mom is 36 but looks not older than a fit 20 year old, which made want every inch of her. She was stunning, with short brown hair to her shoulders and plump B cups that I enjoyed looking at when she wore low cut shirts. The best part of my mom though is her ass. She always wore tight jeans even around the house and it could show it off so nicely. Often I had to hide in my room since I’d get boners from looking at her bend over to pick something up.
The problem with my mom is that she lived a pretty sheltered life, so she isn’t really adventurous at all, but in spite of this, her closest friend is very daring. Natalia was my mother’s best friend and she would be around the house all the time. Natalia was much younger than my mother. She was a 26 year old blonde who loved to party and have fun every night. Often she would come by our house after hours drunk, going into my mother’s room to sleep. It was in one of these nights that I had an experience that changed my life. I always thought that Natalia was hot, but when she came home after a night out her clothes and makeup would make me crave her. Her tits were much larger than my mom’s and she was much shorter than my mom as well, but her slim figure only made her breasts seem that much larger. I knew Natalia was kinky, but I never really experienced it first hand, but it always made me wonder what my mom was up to when she was with her.
One night during the summer Natalia came knocking on the door around 12 after she had been out to town drinking.