To the second sentence:
Teve um dia em que ela mandou-o tomar naquele lugar.
A certain day/she once told him to do something to himself.
For effect, "to do something profane to himself, and that had something to with his rear end".
In a sentence I found:
They will know about the night a crazy old man hijacked a national party’s most important gathering so he could literally tell the president to go do something to himself (i.e. f*ck himself).
The site had no qualms, first tried the mild version, then...perhaps the author thought it milder if it was a parenthetical side definition! Irony intended.