go to the end of the line (given by a particular column) via tabs and enter two backslashes and return.

alternatively, if the distance to the given column is less than some number K, go to the next line, tab over T many tabs, hit two backslashes and return.

The main use of this for me would be inside the align environment, and within tables--that way the layout of the align's lines appear consistent automatically, instead of me having to do it by hand.