Fuck her in the ass while she's speaking

Of course, I wasn't done with her yet, so I followed her back to the front of the class and started satisfying myself in a way that would allow her to carry on her presentation. As she recapped the basics of European railway electrification systems, I started unbuttoning her sinfully expensive but extremely form-fitting jeans to finally expose her perfectly round ass. Pulling them and her flimsy underwear down to her ankles, I gently bent her forward so that she was now presenting her rear to me in its full glory. I got down on my knees and started kneading her behind, parting her cheeks in order to get a better view of her neatly shaved pussy, which was starting to glisten, and her tiny, tight butthole. The sight of this was what finally drove me over the edge; I couldn't hold it any longer. Quickly standing up, I pushed her down by her left shoulder, grabbed her ponytail in my right hand, put my left hand on her buttcheek and rammed myself into her.

"The distance between the inside -- AHHHH -- edges of the -- uuuhnf -- rails is defined as... defined as... excuse me...," she stammered as I started spearing her from behind. She quickly adjusted to the situation, however, grabbing the table in front of her with one hand for stability while keeping her notes firmly in her other hand. "... defined to be 1435mm, which corresponds to the North American norm gauge of 4'8''," she carried on, timing her speech pattern to the rhythm of my cock sliding in and out of her tight hole. "Sorry, I've -- never actually -- gotten anal during a -- presentation -- before, but -- I'll do my -- best," she stammered, glancing apologetically at the instructor, who just nodded in full understanding and told her to carry on as best she could. As she went on to explain the finer points of the UIC gauge and its evolution from the Scotch gauge, I kept slamming her, the sound of my balls slapping her ass cheeks nicely punctuating her talk.