Probably the expert referred to a quick restorative nap, e.g. in case of a drowsy driver. Good sleep for good learning article tries to find the optimum for your intellectual performance.

If you drink coffee before the nap, you are likely to awaken earlier as soon as caffeine starts kicking in. This may be a desired effect if we are in a hurry to combat fatigue, and the degree of refreshment may be comparable

However, an optimum nap in a free running cycle will naturally last no more than 30 minutes, and its effect may be short-lived if it is artificially cut short with a cup of coffee

Any suggestions?