When Mary got to the gym she had to unlock the door and was in so much of a hurry she did not notice that it did not lock again when it shut.
The boy opened the door slowly so he would not make any noise as he snuck up on who he thought was Ruby.
When he got to the gym office he seen her bending over thee desk looking for something so he move fast and grabbed her from behind, putting his hand over her mouth so she would not scream.
Mary started to struggle at being grabbed but her body betrayed her as the boy pinched her nipple sending an orgasmic jolt throw her body. As he continued to play with her breasts she was getting more turned on until all thought of resisting was emptied from her mind at which point the boy pushed her over the desk as he slid his rod into her which caused an even more intense reaction from her body.
The boy continued the rhythm until the two of them reached an orgasm at the same time as he shot his load into her.
After he was finished he cleaned up then left the gym as Mary was recovering from all the new sensations she had just had.
At that moment.......