There have been some innovations in swing sets since the last time I paid attention. There's the basic strap swing. Uncomfortable, but it does adjust to any size of bottom. The baby swing looks like a diaper in shape and a bit like a used diaper in color. And finally, the bucket-seat style -- so you are able to swing in back-supporting comfort.
The baby swing comes with a handy Warning/Disclaimer for you to read to Baby -- perhaps as a lullaby.