A Geth Prime.

As they arrived in the Shuttle Bay, which had been cleared out on Tali'Zorah's orders, the quarian techno-dominatrix fiddled with her omni-tool.

"Shepard, there's someone I'd like you to meet." Tali said.

A crate opened, and out of it stepped a hulking synthetic figure. As it rose to it's full height, Shepard estimated it to be about twelve feet tall. It's metallic body was painted an intimidating shade of red. It's flashlight head, as humanity's only remaining Spectre liked to call them, shone with Tali's favourite shade of purple.

"Tali, where on Earth did you get a Geth Prime?" Shepard asked. The things looked a lot more intimidating when you stood before them with no armor, no gun and no biotics.

"On Earth is right, Shepard." Tali grinned, approaching her other toy. "The geth 'donated' this platform to me."

"And what do you want me to do with it?" Shepard asked, though in her "heart" she already knew. Tali ran a process on her omni-tool, and the geth's crotchplate opened. Out came a thick prosthetic cock, worthy of the robot's hulking size.

"You're a synthetic now, Shepard." Tali said,a hint of mirth evident in her voice. "I think it's time you got to know one of your own people."

"You couldn't have set me up on a date with an Avina terminal?" Shepard sighed, looking up at the geth's huge cock. At least this platform was strong...