A lot of people do it by inputting 214 repeatedly in quick succession. Personally I skip the 4 input and do 21 in quick succession. A back dash (44) also usually helps before starting your KBD.
Yes, on a pad it's the easiest way to go 214, but the ideal input is 1414141414, 214 just makes it easier for you to not be hitting 4144414414144414111