So when he texts, answer him naturally, genuinely, authentically.If you find yourself thinking "I don't feel like replying right now," or "I'll get to it later," then don't reply at all, or tell him (tactfully) that you don't want to pursue a relationship.
Then why do you feel the need to do it with your cute coworker who you really like and suspect might be into you?
Treat these men like the mere friends or acquaintances that they are, until they become something more - at which point text games won't be necessary anyway.
I've dated countless women and it has always amazed me how little they know about men.
If nothing else, this blog is an outlet for voicing my astonishment at the typical female's ignorance of the male mindset.
A final note: if a guy seems to be playing games with you, artificially delaying his responses or skipping texts (yes, guys do this stuff too sometimes), I still suggest replying authentically and realistically.