“Open your mouth,” Lance said. The green eyes enlarged. So did the mouth. That was all he needed to slip the O-ring metal into place. “Since your place of origin is still questionable at the moment, I need to keep your mouth open in case you bite.”
He grinned, then secured the head harness under the chin and over and around the head. He could barely slip a finger under each strap. “Not too tight?”
The man shook his head and regarded him with steady watchful eyes. With gag in place, the man swallowed. Barely.
Lance hardened at the erotic sight. Never had Lance felt this much of a thrill in anticipation of fucking someone’s mouth.

Vaughn 1 is a kinky gay/trans sci-fi romance that occurs far in the future.
If you enjoy stories about gay men, you may also enjoy Skid (Black Storm Pack prequel), a complimentary read at most retail site