As a defendant you have a right to not testify at all. You can decide not to take the stand. No one can request you take the stand, and the prosecution absolutely cannot make arguments about your decision not to take the stand in front of the jury.

But if you do take the stand, then the prosecution gets to ask you questions that you must answer (unless there’s a sustained objection about the specific question).

This is why so often defendants do not testify. Testifying on direct (when the defendant’s lawyer is the one asking questions) will almost always help the defendant. But the risks created by exposing oneself to cross examination are massive, so most choose not to take the stand.