(intransitive, , and transitive with direct object the opponent) To stand with the lateral side of one's (usually right) foot touching the lateral side of his opponent's (right) foot and with his (right) hand clasping his opponent's, and to attempt to force his opponent to lose balance to the extent the latter's (right) foot moves even as his opponent does the same to him.
2001, Henry Hart, James Dickey: The World as a Lie:
White witnessed Dickey's athleticism in a more visceral way when they Indian wrestled, locking right arms and right legs and trying to throw each other.
(intransitive, , and transitive with direct object the opponent) From a lying-down position, to attempt to cause an opponent who is lying in the opposite direction to roll over backward by using locked knees.
1902, Horace Butterworth, "Something to Do", St. Nicholas, Volume 29, Part 1
Indian Wrestle. Two boys lie down alongside of each other, with the feet pointing in opposite directions. They lock the near elbows firmly. Each then raises the near leg three times, one or both counting (Fig. 9). / On the third count they interlock the legs near the knee and try by main strength to turn each other over backward.
1922, William Ralph La Porte, A Handbook of Games and Programs for Church, School, and Home, page 114:
Indian Wrestle: Opponents on backs, right shoulders together, legs in opposite direction, right arms locked, raise legs; on signal, hook feet together and roll opponent over on face.