i'm not being funny but the same goes for kids and for everyone...there is nothing like positive reinforcement and praise to get all people regardless of age to do something....
i am currently training ds to realise that on weekends, mummy and daddy don't get out of bed until 9am (apart from nipping down to get him a plate of fruit and goody bar for his breakfast) and he can join us and chat and cuddle or he can play in his room or be in and out...but we don't move....and it is working!
dh is much worse at this than me and ds runs rings around him in terms of always actively playing with him whereas i sometimes do that, but also ds plays next to me, not always demanding myh participation....like when i'm on mumsnet.
really really important to praise behaviour that you like and never take it for granted....this applies to dh's and kids alike!