I used a lvl 100 tame pachyrhino to tame my 140 megalosaurus :) the first tranq ride the rhyno (the farts keep everything else off you) after that surround with pillars and fart away til it wakes up and repeat!
While fishing, are you sick of all the fish being scattered? If you bring this dino near the shore or on a boat where fish are near by and use the aggro mist, it will aggro the fish to come right to you in a big crowd!
Their “nice” gas might be the gas form of soothing balm. Also it’s effect is to reduce the stamina of everything caught in the “soothing” cloud. Also if it lays eggs why not make its crap soothing balm?