I guess you are right, im still waiting for the dump of bitcoin so i can buy but i think this is impossible to happen for now, so im just focus now to altcoin that i can buy in low price.
I dont know about dump exactly but there are downswings to match the peaks in the BTC price. Its quite a regular market in that way, the appreciation is rapid for sure but its not quite straight up.
So heres a chart and I've marked places of support and boundaries to its upwards climb. If you imagine a kind of staircase at a more slight angle and the jagged up and down that staircase takes while still going upwards, this is how graphs while bullish allow you to buy in:
There is no certainity, but at points its worth more of a gamble then other times. Some people can tell when its due to sell off but thats harder to do when the overall trend has been up for a while now, much safer to try for a regular buy after something of a pullback.
This graph is the last fortnight roughly