An amazing picnic

I went on a picnic with a friend in her mid 40s. We had fish and chips near a lake in a botanical gardens laying on a blanket. I started to slide my hand up her dress and slid my finger up and down her crack over her wet knickers then slid my finger inside her, she was so wet and turned on that she pulled her knickrrs off and i did her from behind. It was so hot, she loved it and moments after we finished a lady walkeo past with her dog and stopped for a chat. We eventually collected our things and walked backmto our car, as we walked kept commenting how my cum was filling her knickers.