The snake had come out from a crack in the wall. He dragged his yellow brown soft-belly over the edge of the stone tough and rested his throat upon it. Then he started sipping water from the place where it had collected in a small clearness. He used his straight mouth and straight gums to sip water silently into his slack long body.
Alliteration –
(a) He sipped with his straight mouth.
(b) Softly drank through his straight.