"Suppose I truly am your heating blanket," Aziraphale murmurs, not unhappily, and gently slides his hands over Crowley's so he can slowly lead them further up under his sweater, before lightly pressing them to the soft, warm curve of his stomach.

The initial contact causes a quiet gasp, since Crowley's palms are cold against his skin, and he releases Crowley's hands so he has free movement.

Aziraphale's face is slightly flushed. He already feels warmer, and that's taking the cold palms into account.