to literallydrop in on a woman when she is bent over during sex; a combination of doggystyle and the jackhammer; where the male goes up and down in a vertical motion
"oh yeah dude, im going to drop in on that for sure."
"She fucking loved it when i dropped in"
A negligible amount. Something that makes little difference. This is especially considering the amount of wealth a richperson has to the amount of spending they do seem to the average person unattainable.
That 40 million dollar homeBill Gates purchased is just a drop in the bucket since he is billionaire many times over.