Just saw "It Follows." IT DOESN'T!

[Solly Mack]

4. The thing, whatever it is, goes after the previous person once the next person is dead.

When she went out on the boat, depending on how many she had sex with, she had 1-3 chances at some more time to live and think of a way out.

So, the entity can't get Hugh (the one who gave it to Jay) until it gets Jay.

Jay has sex with Greg. Greg dies. Now the entity is coming back to get Jay.

Jay has sex with the boys on the boat. Time bought.

They die is the implication - back comes the entity.

They try to kill it in the pool.

Paul and Jay have sex and then Paul has sex with a prostitute, just in case, is the implication. He was driving around street corners filled with prostitutes.

In the closing, Jay and Paul are walking hand in hand, with someone behind them following them.

Implication being, the prostitute is dead, Paul is next, then Jay again.

Did that help?