I can't really answer this with clarity as it depends entirely on a number of big variables like the persons preferences, the location, how well I know them, time I've known them, available equipment/accessories/toys/games etc.
Some littles dont like diapers, some prefer training pants, some like to wet and soil, some only wet, some neither, some are well behaved others can be bratty or anywhere in between, some are fine with harsher punishments (like spanking/paddling) others absolutely hate that, some littles like a bit of independence some want everything done or chosen for them...
Any kind of play interaction between me and a little needs to be preceded by a discussion of what both parties would like/expect whether that's right before we start or in advance of meeting.
If it's someone I've not long met or only look after very rarely my rules would be different to a partner that I live with. Similar with location, if it's my house or an event then yeah probably no throwing food or getting too messy, if it's their house and they are fine with some mess then why not, throwing food at that point is a good way for a little to get supported/reprimanded/punished without having to step out of their little space to plan it.
I do have definite rules for changing...
I am happy to change wet diapers/underwear for anyone of any gender if asked nicely or during a play session but I will only change messy diapers for people I know very well or see regularly even then there may be times where I just don't feel like it so I would say before anything began if it was ok to mess, if I don't say so then assume it's a no. If it's a partner that I live with though I would be fine with it for the most part only saying on occasion when I really don't want to.
If it's wet underpants there may be an aspect of forced diapering or some minor punishment depending on circumstances and if I've agreed to messing then dirty pants are a garanteed diapering and possible spanking (if that's agreed to).
I won't change in public places unless a very private location can be found (or the public location is an abdl event).
In addition any change given by me will be completely non sexual, unless it is with my partner or a little I have seen often enough and it is agreed that it's something we'd both like.
This is one of the biggest reasons I came up with the coloured bracelet/hairbow etc. Plan I have explained it in
This Post a while back. The basic idea is that you have a number of differently coloured bracelets/bangles/hairbows/collars/necklaces and each colour represents a different feeling, need or desire. Both the little and the CG can wear these and a chart explaining what each colour means for each side can be available so for instance:
If a little one is coming to me for a play session and they are wearing or ask for a white hairband I immediately know they are feeling completely like an innocent baby and want me to take full control treating them with lots of love and patience, on the other hand if they turn up with a red band I know they are feeling naughty will likely be misbehaving and it's ok to spank them. Conversely if that little one wants to poop, looks at me and sees a yellow bracelet they know I am not in the mood to change dirty diapers, it may still be ok to do it but they will be changing themselves. or if i'm wearing a green band I'm feeling ill and don't want to much noise or pestering.
It works best for partners as you can memorise the colours better and just live as you both choose without having to talk through things every time but is also good for people meeting rarely as it saves breaking headspace to explain what you both want/expect. It is a good way to communicate things between little and CG without words.
I may have some hard and fast rules, one of which is that I do not accept the title of "daddy" from anyone until there is a stronger bond between us and we have a better understanding of each other, that is a title reserved for those who have gained my trust and whose trust I've earned. On the whole though my rules/routines and expectations are negotiable to an extent with each person that wants to have me as a CG.
