Griffin gets easily distracted and finds it hard to stay in a SIT for more than a few seconds. It’s important to be consistent and patient when working with him. If he gets up before being released, you have to put him back in the same, exact spot every single time (with out repeating the SIT command since the 1st one stills applies). He will eventually learn to SIT until released, but not if you don’t expect him too! Start with quick releases, then work towards longer and longer SITs as he gets older.