Tahm Kench W

Hello, I just started to play Tahm so maybe it's not a bug but my bad play. When I swallow someone from my team I can control in what direction I spit them out or not? It usually works but there's been a few times, specially in early game where I swallow my champ to get him into safety under our turret ( i hold my mouse infront of me in the walking direction and left click as well), but then the adc suddenly gets spit out over my back behind me back into the enemy.

Am I doing something wrong? :D