Remove the underscore:

    $ ping _why.usesthis.com
    ping: unknown host _why.usesthis.com
    $ ping why.usesthis.com
    PING why.usesthis.com (74.207.245.100) 56(84) bytes of data.
    64 bytes from waferbaby.com (74.207.245.100): icmp_seq=1 ttl=53 time=178 ms
    64 bytes from waferbaby.com (74.207.245.100): icmp_seq=2 ttl=53 time=178 ms