I think you're thinking of spring and neap tides. During a spring tide, the Sun, Earth, and Moon form a straight line, which makes both sides of the Earth have high tide like this
so the moon IS technically on the opposite side of one of the high tides, though directly above the other high tide.
Neap tide is when they form an "L" shape, causing the gravity of the Sun and Moon to effectively (at least partially) cancel out, like this
(you probably know all this but I just wanted to make sure we're on the same page)