To answer your question, if I am holding a large amount of cash that I want to be immediately available at an undetermined future point in time, I park it in a savings account with up to $250,000 per bank. The $250,000 limit per bank is to get full FDIC coverage. So if you have more than that, you need to open an account with more than one bank. Discover, ally, goldman sachs savings bank, and a handful of other banks compete with each other to have the highest savings rate. GSBank is currently offering 1.2%. You just sign up online, transfer via ACH from your current bank, and start collecting interest. When you are ready to use that amount, you transfer out the balance to your bank via ACH, or ask for a check, and close that account. Easy peasy. I stay away from CDs (because they tie up your money) and bond funds (because they can go and probably will go down). Money market funds like the ones at Fidelity and Vanguard are not FDIC insured, but these giants are unlikely to go bankrupt anytime soon, so the difference between 0.8% and 1.2% may not be worth the effort depending on how much you are talking about. But you are still paying fees with money market funds and personally, I loathe paying fees no matter how miniscule, so I have personally gone through the trouble of opening up one or more savings accounts.
With regard to buying the dips, I agree with others, that you should probably not try it unless you know what you are doing. I would say the best course of action is to put a time limit on yourself. So try to "buy the dips" as best you can for the next 12 months, and if you still have anything left after 12 months, commit yourself to putting the remainder in all at once.
Also, buying on 2% dips is not a rational strategy for market timing because it is too small of a change. What happens between those 2% dips is likely to be much more significant. Buying on a 10-20% dip is a more rational approach, but you have to recognize you may not see that for years, and in the meantime the market may rise much more than 10% while your cash is sitting in a savings account earning a measly 1.2%. You also need the guts to buy when that dip occurs, because a lot of people will be saying that the market is for sure going to continue going down another 10% at least, and they may be right. If you do want to try to time the market, all that matters is your overall opinion on the direction of the market. If you think it is going down then you wait till it goes down to what you think it should be at. Your opinions need to be based on facts or better yet, numbers, that can be tracked. But above all, you have to recognize that you may be wrong with your opinion. Therefore set a time limit for yourself and keep it. If you are wrong, cest la vie, dump the rest in a low cost index fund and go to the beach.