Why does he do this? Please answer its urgent!?

So on Friday this lad that I heard of my age lives near me everything blah blah blah started talking to me and he was being super sweet. Then he asked me for pics and I sent because I'm old enough and its legal for sexual actions for my age (I'm 18) anyways, then on Saturday he didn't message me except for once when I said he was 10 out of 10 and he said 'Thankyou baby' then today at lunch he messaged me and we sent again. He hasn't messaged me since 1pm. What is he doing? If you're a guy reading this why do you do it ? It's disgusting you use girls just for your ho*ny needs!