People don't pay close attention

Both of us walk into our Math class. The only seats are right in the middle of the class. One in next to the other. The other classmates always leave us these seats. The teacher and students ignores us. Class progresses as normal, and you can see Sam getting more and more bored. She glances at me from the corner of her eye and gets a massive grin. I see her reach her hand behind my seat and place her jacket.

"Don't make any noise. People will start paying closer attention and might find out."

"I wasn't planning on it. Why?" The reason shes saying this is making my heart beat. I see her reach her hand down. She starts rubbing my butt. The shock of being touch make me almost jump to my feet. I resist to the best of my ability. This reaction interests her. She started rubbing my body all over. Her favorite reactions when she slowly rubs straight down my back. She looks at me before class ends ans says, "Ehh. Whats...?"