Is it possible to do back to back tourist visas in Thailand?

Not an issue for one or two. It’s quite normal for a tourist to travel to Thailand, exit to somewhere else and come back for a while.

That said after one or two back to back you’re open to them questioning you on your intentions. The embassy may not issue, or the immigration officer may ask you why you’re trying to enter so many times without a long term visa. Nothing is set in stone. You could have six back to back and no one says anything. You could have two and get asked.

There is not now, nor has there ever been a rule against doing this.

Most of the consulates around Thailand will issue you a 2nd and possibly even a 3rd TR back to back before they start asking questions. But eventually you will get pushback from both the consulates when you apply, as well as immigration upon entry about why you are doing this.