Webbing Strap Padding/Protection

Got my best friend one of them doggie bag packs. He loves it and runs round like an idiot when i put it on him as he knows he's off for a good trek.

Unfortunately one of the webbing straps has started to rub him under the chest and leg so need some sort of protector.

He's a bit of a water baby ie will not hestiate to jump in a tarn of stream so need it to be better than just a piece of foam.

Anyone any ideas? 

I know this will be hard to answer - does the harness rub when its dry, when its wet or both?  If both, it may be a touch tight - can you slack it off?  If it is tight, adding padding will just make it tighter so exacerbate the problem.

I have a harness for my furry buddy and was amazed how big it had to be once it was properly measured (how can a Jack Russellx  be a medium dog but he is)

Instead of a bit of CCF mat, get yourself down poundland, they do a poor mans version of a pile/pertex dog coat for £1 -pair of scissors, bit of thread, pile side in so its fur against fur?

Thanks guys, food for thought, like the cheaper option GOF

I tried to slacken it off but didn't help, i think the rubbing is caused because he runs all over the place rather than walk (except when on his lead) so would imagine i would have similar issues if a was running with a rucksack ....... topless!!