[Ayoka]

I have been using the clicker for training and I would only click and reward at a high rate when the dog is in a sit and do nothing when it slides down. Basically the idea is to make the sit more rewarding so he's more likely to do it. We started the sit/stay by asking for a sit and waiting a few second then releasing him with "ok" then gradually waiting a feew more seconds before the click and treat and so on.

My guy has a hard time in the sit on slippery floors too so we generally practice longer sits where I know he won't be encouraged to slide down by the slippery floors.