Has anyone used this, or have experiences of it?

I am looking at it as an option for an entire 2yr old BC who is shown. Day to day he is lovely, but whenever we are out in public at things like dog club, he seems to spend the entire time bitching, sniffing and scenting and I can't cope any more. On walks, he has a perfect recall, in groups or alone, but at training it all seems to go out the window?! It happens at obedience or agility, and sometimes at show handling but no-one is quite sure why? It doesn't seem to be due to boredom, or confusion, as he can be working fine, then loses track and off he goes..

If you want to show then don't use it as his testes will shrink big style, plus there is a risk of permanent infertility.

I've used it on my 9 yr  old male Jan of this year for the first mths I had to have tardak jabs done as well coz he was worse than ever on the sex drive side of things.  I was using it for his enlarged prostate and at his age fertility wasn't an issue, hes still got small testes 10 mths down the line and infertile so the 6mths hasn't been right for my dog but each animal is different.

I can't show him in Veteran either till his boys grow again lol.

Showing is something I enjoy, but isn't my sole reason for having him, so the testicle shrinking is something that doesn't concern me too much, especially as we don't have another big show until April :) And the infertility again isn't a worry as he has an endorsed registration.
I feel like I need to try something with him as training or drilling seems to have had no effect :( but I don't want to do the suprelorin (or all out castration) if it'll have no effect?

In my experience the Supreloin does increase their sex drive for the first few wks hence a good vet will recommend Tardak first then the implant a couple wks later with a 2nd Tardak if the overdrive is still obvioius longer than anticipated.

A tardak jab can be a good starting point see how he goes with it and if you can engage his brain during those difficult times when the external stimuli is just overwhelming

Probably unlikely but do you think the sniffing could be due to stress? Maybe when hes working it all gets too much and he needs time out he sniffs as a dispalcement activity? My spaniel does this when stressed, but its hard to actually tell he's stressed until he switches off. It probably is more likely hormones but worth considering as a possibility if he is ok out on walks when doing his own thing.