It means “people will start getting drawn to you”. It is a colloquial expression. I usually heard it being used as a part of a phrase «Будь проще, и люди к тебе потянутся» = “Behave more simply, and people will start getting drawn to you”. It is used to tell a person he/she is acting too “cool” to be really cool. It is not an insult, though. Sometimes I also heard the full expression being used as a joke to tell shy people they don't need to distance others away and be more approachable. I guess, overall it's a slang version of “Care about what other people think, and you might start getting popular”.

People will stretch their arms up to you (in figurative sesnse). "Not stretch your arms if you do not want to stretch your legs!" (a joke for a greedy person)

Si cambias tu compartameto en manera mas amable , mas simle , la jente empezara entenderte mejor y te acercara para hacer cosas .( Cuando algien hace movemiento mental o fisico a algien o en cualquer lugar una vez usamos una palabra coloquial - потянуться , тянуться ) Espero que lo quedó claro .

People will want to speak to you

= People will be attracted to you (in generals sense, not in a sexual way) = You'll become attractive (in generals sense, not in a sexual way)