Here is my first 2016, Canon MT-24ex Twin Flash diffusion setup for use with the Canon MPE-65mm . It is from packing foam ( the stuff you get in some parcels).
I have doubled the foam up and then taped it. After that I cut a hole to allow the Canon MT-24ex Flash heads to go through. There is also a bit of the packing foam loosly taped to each head.
I use velcro to “roll” the material up from in front of the lens. I also sometime attach a partially cut water cooler cup to push it up. I have not photographed that yet. But will add a picture next time I use one.
Here are some images that I hope explain what I have at the moment.