Helping my Pregnant Sister

I was 25 when my older sister Lauren got pregnant with her 2nd child.  She was 29 at the time and married. They already had a 3 year old. 

One day Lauren called and asked if I could help her out with a few things. We were pretty close and I helped wherever I could. She had me pick up a few things at the store for her. I went to her house to take her stuff and see what else needed to be done. She answered the door in her robe and said her kid just went down for a nap. She explained she needed to shower and I could hang out if I wanted. My sister and I have always been close but never anything sexual. I've always been turned on by her though. 

She finished her shower and came back to the living room in her towel and a towel for her hair. I couldn't help staring at her. She was about 5 months pregnant and her belly held her towel slightly open. She had on a pair of pink panties she wasnt hiding. She noticed me staring and asked if I was checking her out. I told her, "I was a little bit, you're very pretty." She giggled and opened her towel to rub her belly. She asked me if I thought that was hot. We laughed. I was getting quite turned on. She was brushing her hair and thought she wasnt looking when I adjusted my hard on but she saw. 

"Oh little brother do I really turn you in that much?"

I told her yes.

My big sister shocked the hell out of me. "Do you want to take care of that?"

"Excuse me?" I asked. She said, "Masterbate." 

I told her I would but with her there? She told me how horny her pregnancy made her and that she was about to herself. She said she was going to her room to get off real quick and I should come watch her. I eagerly followed her. 

We got to her room and she took her towel off. I asked about her husband. She told me that we could masturbate together. She said they had an agreement. I stripped nude and laid beside my sister. She took her panties off. I asked to see them and took a big whiff. I told my sister how good she smelled and my cock throbbed. She spread her legs and put her hand on her pussy. 

She asked me if I ever smelled her before, and I confessed numerous times. She stuck a finger in herself then placed it on my mouth. Here try this. I told her I was going to come. My big sister grabbed my cock and stroked it until I came all over her hands and my belly.  She tasted me and rubbed my cum on her pussy. I leaned over and sucked her nipple as she orgasmed next to me. We sat a moment then she kissed me and thanked me. I told her it was a dream come true. As we laid and talked I got hard quick again. Lauren grabbed my cock again and began stroking it. She told me I could touch her too. I gladly felt her wet pussy. I told her she was first this time. I rubbed her clit and fingered her wet hole. It didn't take to long and she had an orgasm. She started jacking me and we talked. I soon came again. 

We had a really good talk afterwards and should be part 2.