EVery buy is a sell... The transaction of a trade is the exchange of shares from a buyer to a seller..
Dont believe into all that MM hype...
If I put a buy in at .0023 for 123456 shares, and "Joe" sells 500,000 at .0023 you'll most likely see a trade of 123456 hit the ask/bid...
On occasion the MM's will clump the trades together, and show a block on the L2.. MM's do control the size's of blocks on occasion, but majority of the times a trade goes off in the size you put in...50 million in volume means there were both 50M shares sold, and 50M shares bought.. Its a simple exchange of shares from one seller to a buyer..