Entry and exit
We always do zazen, or mokuso, in our aikido classes. I like to have a rather practical approach to it in aikido practice. It encircles keiko.
Before starting the practice, we do a short meditation, mainly to empty ourselves of everyday life distractions and to begin budo breathing and such. At the end of the class, we finish with a just as short meditation to bring ourselves down to everyday life rhythm and power.
So, mokuso becomes a kind of on and off switch for keiko.
Of course, it can become much more - but that sort of happens by itself, given time.