"Mwahohoho! Chad, you're not an elf on shelf anymore, you're going to be my elf on my shaft!"
"Oooh!" shrieked Chad as he felt his body changing in his unremovable rubber elf suit. It stretched to fit his new shape. His legs grew longer, and wrapped around Nate's cock root behind his balls, and his feet fused together. His legs now formed a green rubber cock ring for Santa Nate. Chad felt his torso stretching, as his arms grew to embrace Nate's thick cock. Chad's face was buried in Nate's velvety penis, and his arms fused together in a ring around Nate's shaft. His tight grip helped engorge Nate's cock keeping him erect.
Nate laughed, and admired how Chad's induced boner tented his red rubber Santa Suit.
Chad could only cling tightly to his new home. He was Santa Nate's Elf on His Shaft now, and he had a bad feeling that he would be here for a very long time.