think of something bad, a tragedy perhaps
breath in
savour the clusterfuck of air particles that youve insufflate
let them linger in the different threshold of your lung
inhale till you cant feel no more, the brittle feel of your ribcage collapsing & sinking itself into your blooded flesh
tear droplets will be discarded by your eyes soon after
expect a slight pain throughout your whole body
feel free to scream, laugh or even go on a rampage during this process
for those who are well versed in the ancient art of crying, they may experience symptoms such as the urge to puke, disorientation & other health issues
remember practice good breathing rythm in order to avoid suffocation & death

feel free to improvise along the way to ensure maximum enjoyment in this activity
if done right, you'll find that crying is addictive in a theraupetic fashion.