I used a swing, but with regards to your swaddles and sleep sacks, I just made slits in the back that lined up with the harness. So I would lace the harness through the back of the swaddle, insert DD, fasten harness and zip up sack/swaddle (we used Woombies...LOVED them). That way she was safely harnessed while she slept, nice and warm in her sack, but rocking away. We did this for the first 6 weeks until I transitioned her into her crib. Good luck!