Wiktionary describes a tuit as:
This is a play on words, from the idiom to get around to it.. First appearing in print in the 1970s.
round tuit (plural round tuits)
1. (humour) An circular object giving it's owner the ability to get done everything that would have otherwise been put off to a later date.
No more waiting until you get around to it, buy your own round tuit at a bargain discount today!