To be truly effective, you need to do this manually...
- create the shape then add anchors and move them
- draw by hand and scan/trace.
I think the top option is generally quicker and easier, but takes some "fiddling" to get where you want.
I merely added anchor points to the shape's path. Converted those new anchors to smooth points and moved the handles a little.
To the best of my knowledge, none of the effects are going to be as subtle as your example.
Another option, although possibly more complex than necessary, would be to use an Envelope Mesh.
- Draw the shape and then select it
Object > Envelope Distort > Make With Mesh and enter a good number of columns/rows based upon the object....
- Use the Direct Selection Tool to move handles and mesh anchors around...
A third option would be to use the Warp Tool
- Draw your shape
- Grab the Warp Tool
- Start pushing and pulling segments
Note, my shape does have Effect > Stylize > Rounded Corners applied to it, in all 3 examples.