Sex toys and longevity of use

Let's talk about toys. 
I love me some good erotica and I recently read a short story where the Dom had made the Syb keep a dildo or a plug in her pussy for the whole day. Pretty sure that's a common thing in erotica, but how common is it in real life? What's the best toy to use? And is it safe? Any advice? 
Searching for one with a good but small base so it's not noticeable if I'm wearing anything tight, like pants or leggings. 
Brands and models would be great! Thanks!