When a first mobile user wants a second mobile user to follow him, {HEAD ~ the first mobile user} can put {TAIL ~ his device} in “follow me” mode 
put
When a first mobile user wants a second mobile user to follow him , { HEAD ~ the first mobile user } can put { TAIL ~ his device } in “ follow me ” mode
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH