A coup is when you depart from the ordinary established rules of play, with certain reasons for each special case. Do not hesitate when attempting a coup. Consider what the play of your adversaries means, as well as that of your partner.
Bear in mind that coups are justified only in exceptional cases.
In all these cases A and C are partners. A is the dealer, and the discard is supposed to have been properly made.
CASE I.
Refusing to over trump.
A
D
B
C
Score, love-all. A adopts the trump.