Her mom doesn't find him

"Rachel, what are you doing? I heard strange noises." Her mother sounded worried.

"Um, ..., sorry. I-I was just having some, ah, private time. ahem" His lab partner sounded nervous and embarrassed, as she should for the tale she was selling.

"Oh! Dear! Um, I'm so sorry. Don't let me interrupt you." Her mother closed the door and fled as quickly as possible from the knowledge that her daughter was masturbating.

At the sound of her retreating footsteps down the stairs, he heard Rachel whispering under the bed, "You can come out now, John. She's gone."

He crawled out.

"Perhaps we need to work on making less noise as we continue our research," he said hopefully.

Rachel smirked at him. He could almost see the gears turning in her head. Then she said, "Saturday morning, my mom and dad go to garage sales all morning. I very much want to continue this research. By the way, thank you for taking my cherry so well." She kissed him long and deep.

When she stopped, he said, "Thank you for giving me that honor. Saturday sounds like a lot of fun."

Rachel resumed the kiss and fondled his cock. She got him back to attention before she broke the kiss. He started getting dressed, his erection getting in the way. She giggled. "Okay, now out the window. If you walk carefully on the roof over to the south edge, there's a very sturdy trellis you can climb down unnoticed. I've used it a few times. If you head to the front yard, John, keeping your head below the windows and staying close to the house, you should be able to get away unnoticed."

Once he'd dressed, she kissed him again, and again fiddled with his junk. He was rock hard when he stepped out on her roof.

He had a dicey moment when walking on the roof as quietly as possible. It was still wet from the rain in the morning. He lost his balance and windmilled his arms for a few seconds before recovering. He made it to the trellis no problem, but it wasn't as sturdy for his 195 pounds as Rachel claimed for her 125 pounds. The trellis creaked and strained. He managed to make it to the ground without greatly damaging it or himself.

He snuck around the house without a hitch, and then he walked across their front lawn like he had just walked between the two properties. He made it home without incident. His head was filled with lusty thoughts of fucking Rachel bareback, breaking her cherry, giving her an orgasm, and coming inside her. This was the best science project ever!