Yes - it is great idea and possibly lots of fun - but if you want her trained properly - TG mentioned earlier - it should be done on regular basis - every day, every other day - you should start with the smallest plug and work your way up - i would not start with moderately sized - rather with smallest one and work your (hers) way up to larger ones.

You do not need the topic aesthetic – just lots of lube.

In the beginning she should be able to tolerate plug inside for good 2 hours before it is really uncomfortable (some could do it longer), when she is comfortable for a while with small size for a period – I would say of some 6 hours at the time – you can increase size.

Depending oh how much and how often you have access to her you might want to have her wearing plug on daily basis – to get used to the feeling of fullness and to be relaxed enough for you to take you easily.

I think – unlike vaginal probes – the but plug is impossible to forget about – it is constant reminder of intrusion and such a “nice” way of having her thinking of you.

I personally think it is great to have that combined with enemas – another great humiliation play – that also serves as a tool to cleanse and makes sub more at ease with anal play (in most cases – cause it is clean).

And again
such a gorgeous but plugs for serious players

good luck and have fun

P.S. just as an after thought! Stick it up your ass – and see how it feels – nothing better than first hand experience