This was a very foolish thing to do.
There will be demands for ALL of his tapes (not just those with Comey), and lawsuits when he doesn't hand them over. The courts will rule they must be made public, and then he faces two choices, both bad:
- hand them over, allowing his enemies access to his secrets; or
- refuse, and be branded as another Nixon.
Trump is turning out to be a horrible disappointment, and although he has plenty of helpers it's mainly his own damn fault.