There are bits of Sugru on some Lenovo chargers where the cable pulls from the charging unit. This is precisely what you're describing and I've moulded it to still have some give (tapers away from the plastic charging unit).
And some bits on Brompton (cycle) pedals to add weight so that the pedals swing to a better starting position.
A walk around my house will reveal little bits all over, each doing a small thing and sparing me from the cost and waste of replacing larger things.
It works really well and the only complaint I would have is that it can be ugly. But more than anything that is your choice about which colour to pick and how you shape it before it sets. I now use a tool to shape it (back of a teaspoon, etc) so that my finger impressions don't live forever and make it look kinda amateur.
Works well, would definitely work on the kind of small fix you need.