Bad Bunny's giving golf tips to Happy Gilmore ... because the rapper is filming scenes with Adam Sandler for the upcoming sequel -- and it looks like he's a caddy.

However, this highly unorthodox swing, despite looking so freaking cool, goes against everything you learn at golf lessons ... Adam Sandler in Happy Gilmore The Time He Rode His Club Like A ...

If you've ever played golf a day in your life, then chances are you've tried to do "the Happy Gilmore." You know, a tee shot where you start a couple yards behind the ball, take a two- or three ...