On Top Of Meaning
(idiomatic) Fully informed about, and in control of something; up to speed with.
Very close to, in any orientation or in time.
Living on top of one another in a refugee camp is stressful.
At peak times, a telephone operator must handle a number of calls, one on top of the next.
. . . and on top of all that, I got a puncture!
I have sorted out the problems and am now on top of the situation.