Whistle on Technical?

[mcdanrd]

Does the mechanic for a technical foul always involve a blast of the whistle? Had a situation last night where the number one girls HS team in the state was up by about 20 on an unranked team midway 3rd quarter. I call a foul on girl from unranked team and coach immediately calls a time out to discuss the call. During the course of the conversation he informs me that I am "a terrible official." I respond with a blast of the whistle and the good ol' technical foul signal. Was the whistle necessary/required or could I simply have informed the coach, scorekeeper and partner?