studying with a friend from university we were studying and look what we ended up doing

I go to a university classmate's house to study because she is not very bright, it is very difficult for her to calculate, she asks me for help, I try to explain but she still doesn't understand how I already knew the answers to the exam, so she tells me that she help with the answers then I make her pay me in kind I make her suck deep throat and then I penetrate her delicious