A Cluffy Wedge is a trademarked device that is used in shoes, on insoles and on foot orthotics. It was developed by the Podiatrist, Dr James Clough, DPM primarily as a way to treat functional hallux limitus. The Cluffy Wedge is placed under the hallux or big toe to hold it in a slightly dorsiflexed position. For more on the Cluffy Wedge, see this.
As the Cluffy wedge is a trademarked product and marketed as such, you technically can’t make your own Cluffy Wedge. However, a lot of foot orthotic labs and clinicians use padding under the hallux to work in a similar way to how a Cluffy wedge would work. They call this padding or addition a number of different things.
One way to do this in the short term is to use podiatry felt on the underside of an insole from the shoe:
This is an excellent short term measure. It can be made quickly and trialed to see how it goes. The podiatry felt will last long enough to get a feel if this is what is needed in the medium to longer term. A more permanent material or as an add-on to foot orthotics can be used if the short term trial is successful and indicates that this is needed.
(Note: this pad is more distal and the Morton’s extension pad, which goes under the first metatarsophalangeal joint, whereas the Cluffy Wedge goes under the hallux).