A/N Ok some background information:
Grissom and Sara are married and have a son who is 5 called Mark
Grissom has been having his on and off affair with Nick for about 5 and half years.
I'm only borrowing the characters except Mark he's mine.
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"Honey, I have to go to a conference in, Dallas." Grissom told Sara, she looked up at him "That's fine Gil, but when is it?" she said before going back to looking for Mark's missing sock. "I'm taking Nick with me; he wants to visit his parents." Sara stood up after finding the missing Barney sock "when is the conference?" Grissom looked at her and told her it was next week, the conference was 3 days but he and Nick were staying for an extra 7 days he was guest lecturing at the local high schools and middle schools, Nick offered to help. Sara looked at him angrily "Gil, you'll miss Mark's birthday!" Grissom looked down at his feet, "I know honey, and I'll make it up to him." Sara gave up she knew Mark would be devastated his father wasn't there, but she wasn't going to make a huge fuss over it.
5 days later and Grissom walked into the terminal at the airport holding Mark in one arm and holding Sara's hand with the other, and Nick walking behind them. They checked in and Grissom said goodbye to his family, when Mark realised his dad was going he started to cry. When they got through security and were seated in the terminal Grissom looked at Nick, Nick grinned and told him they had a connecting flight to New York at Dallas Airport in 3 days (after the conference). "That's great Nicky. I booked us the Plaza hotel." Grissom told him, Nick looked at him shocked "Gil that's a really expensive hotel" Nick said as he looked at his lover, Grissom laughed "I'm dragging you to a two day entomology conference, then shopping for my wife and son to make it look like we were in Dallas for a little while. This is my way of making it up to you." He said before kissing Nick quickly on the cheek.
Grissom figured since he never got any quality time with Nick he'd try and make the most of the flight, "Hey Nicky?" Nick looked up from his book "Yeah Gil?" Grissom smirked and asked "So on my honeymoon I was inducted into the mile high club by Sara, I can't say it was the best experience, have you had a better one?" Nick felt a familiar twinge in his pants and figured what Gil was up to he leaned over and whispered, "I'm not having sex with you in an aeroplane bathroom." Grissom smirked and thought 'yeah right Nicholas Stokes.'
Through some obvious fowl play by Grissom, he and Nick did have sex in the aeroplane bathroom and it far surpassed his past experience with Sara. When the plane finally touched down Grissom, had succeed in not only having sex in the bathroom, but making his lover cum in his pants whilst describing what he was going to do when they got to the hotel.
After collecting their bags, Nick dragged Grissom to the cab making sure he fulfilled his promises that were made on the aeroplane.