How to make him a better kisser!

Okay.. so this is emberassing. But I really like this guy and we've been hanging out a lot.. dating, kissing, acting all loveydovey. I do like him, but theres one problem. He really cant kiss. He's 19 and when I asked he said he had 2 girlfriends before...

me so he madeout with 2 chicks before but it doesn't look like it.. he really cant kiss! His mouth is wayy too far open and he just sticks my tongue in my mouth and starts killing me with it . How the eff do I let hem know he's not that good without hurting him? I already tried saying that we might have to practice kissing a lot cus practice makes perfect.. but I think he took it the wrong way . And its not like I can gently try to learn him how to kiss cus he keeps shoving his tongue deep in my troath . I really dont know what to do . helpp meee