“Breathing in, I calm body and mind. Breathing out, I smile. Dwelling in the present moment I know this is the only moment.”
–Thich Nhat Hahn: Being Peace

When you know what the focus of your in breath is you can simply repeat:

[In] “Present Moment”
[Out] “Wonderful Moment”
[In] “Smiling”
[Out] “Calming”

…and repeat for as long as you’d like or need. You can do this anywhere to bring yourself back to now, back to the present moment.

And it’s free!