let us see an authentic narration from musnad ahmad

jabir says that when we would offer zuhr prayers with holy prophet asws, i would take handful of pebbles and keep it in other hand, and when they would cool down, i would prostrate on that. because it was too hot

[musnad ahmad, urdu version, vol 6, page 129-130]

translator of the book, molvi zafar says it is sahih as per ibn haban and hasan as per albany

sheikh shoaib has termed this narration hasan in his research upon musnad ahmad

[musnad ahmad, with research of sheikh shoaib ul arnawut, vol 22, page 386, narration 14506]

thanks God, this act of sahabi will clear the point that prostrating “on” something does not mean prostrating “to” it
and no more would people say that shia prostrate “to” their sajda gah when they prostrate “on” it
if they say so, they have to apply the same charge on that sahabi as well