Seeing as both Aharon and his sons leaned their hands on the bull, why does the Torah write "Vesamach" (in the singular)?
Or ha'Chayim (citing the Tosefta): 'If five people who Shecht a Korban, each one is obligated to perform Semichah, not all at once, but one after the other'. 1
See Oznayim la'Torah, who explains why the Tosefta derived this from this Pasuk. He also queries this explanation from the Eil ha'Olah, in Pasuk 15, where the Torah writes "Vesamchu" (in the plural), whereas in Pasuk 19, regtarding the Eil ha'Milu'im (the second ram, the Torah again writes "Ve'samach" (see the Oznayim la'Torah's extensive elaboration)
Where exactly, did Moshe Shecht the bull?