I remember these times. We tried lots of things. Some of them worked. But most of them worked once and never again. And so we had to adapt constantly.
My oldest niece was probably the trickiest child in our family about this. I swear she had some sort of crazy radar that told her when the holder's butt cheeks hit any surface. No sitting allowed! So not only did her parents and all of us have to hold her constantly, but we had to hold her and stand. She's lucky she was our first baby. :)
My older son really liked to be swaddled tightly in his bassinet alongside the ocean music box that clipped on the side. My youngest was a swing guy. And when nothing worked, well, that's when I: a) cried a little and then b) put them in the sling so I could at least have arms to do a few other small things.
This is definitely a tough baby stage for parents.
What works for your baby who needs to be held in order to sleep? Have you found a solution or do you surrender to the constant holding?