Does a 'substantial step' under 18 U.S.C. § 2422(b) require evidence of intended 'Interpersonal physical contact' in order to rise to the level, and/or meet the definition of, 'sexual activity'?

QUESTION PRESENTED 1) Does a “substantial step” under 18 U.S.C. § 2422(b) [attempted coercion and enticement of a minor] require evidence of intended “Interpersonal physical contact” in order to rise to the level, and/or meet the definition of, “sexual activity”? i