Ask for a lawyer, then stop talking.
Say it out loud and say it plainly. Questioning is supposed to end once you clearly ask for counsel — but that only works if you actually say it, and then stay quiet afterward. Asking for a lawyer and then continuing to explain yourself undoes the whole thing.
You cannot talk your way out of an arrest. The decision to charge you has already been made by the time anyone is asking questions. What you say next only affects how much evidence there is.