S&P 500 is going higher and higher each day. I have planned to DCA into S&P 500 but can’t seems to do it as I’m afraid that it might crash all of a sudden.

If you're not comfortable with high potential losses, probably go for a more stable investment. Robo investment e.g. Syfe/Endowus. They can cater to different risk appetite.

Periodic up and down maybe. Crash no. Fed taking same policy to keep printing $ ( unlimited QE) like Japan. Even if It goes down , longer term will still go back up because Wall Street bank rolls the G and they can't afford to lose $. Doing nothing and miss riding the tide means lose out more due to unlimited QE caused inflations and future value of portfolio lose out even more.

I do DCA into S&P via Vanguard S&P 500 ETF via FsmONE...it allows me to moderate the amount and I personally think S&P is a long term investment...so its a form of forced savings for me too. Just sharing my own personal experience ;-)

Cannot be!!! S&P500 price can go up and down and but its price will not move sideaways for a few years. If you really look at the charts for S&P500, the price will usually go sideways for a while if there is a market correction. This will not take years my friend. Are you looking into S&P500 or some other mediocre stock ticker? STI index price can move sideways for many years but not for S&P500.