S.D. Codified Laws § 15-26A-74
A brief of an amicus curiae may be filed only at the request of the court or by leave of the court granted upon motion and notice to the parties. A motion for leave shall identify the interest of the applicant and shall state the reasons why a brief of an amicus curiae is desirable. An amicus curiae shall file its brief within the time allowed the party whose position as to affirmance or reversal the amicus brief will support unless the court for cause shown shall grant leave for later filing, in which event it shall specify within what period an opposing party may answer. An amicus curiae brief shall not exceed the page limitation set in § 15-26A-66.
Amici curiae counsel will not be entitled to participate in oral argument unless counsel for either party agrees to share his time and the court allows the appearance of amici curiae counsel.
SDCL 15-26A-74