Perhaps it would be clearer by going back to first principles for patents.
The purpose of a claim is to set out certain things that others cannot do. Once a patent is granted, nobody else can do anything that is claimed. This is true regardless of the category of the claim (whether method, apparatus or whatever else).
It is therefore not correct to say that "[the patentee] can implement the technology as software and also as apparatus having that software". A patent does not give any rights to do something. A patent is solely used to stop other people from "doing" the claimed invention.
What does it mean to "do" a claimed invention?
A method claim involves a series of steps. A method claim is "done" by a person performing all the steps (in principle, this is regardless of how those steps are performed, such as using a computer, on pen-and-paper, etc). If you claim a method, you will be able to stop a person doing those steps.
An apparatus claim involves some physical object. An apparatus claim is "done" by making, using, offering to sell, or selling that physical object. If you claim an apparatus, you will be able to stop a person from making, using, offering to sell, or selling that physical object.
A software claim is similar to an apparatus claim, in that it involves a physical object (in the broadest sense of physical). A software claim is therefore "done" by making, using, offering to sell, or selling that software. If you claim software, you will be able to stop a person from making, using, offering to sell, or selling that software.
These categories are generally complementary, as they target different infringers and different infringing acts.
What is the difference between a method and software?
The difference is in the infringing acts, and who would be caught by the infringement. A method is infringed by the person performing the steps of the method. Software is infringed by a person making/using/offering to sell/selling that software.
There is some overlap here. A person using software will generally be performing the steps of an equivalent method. They would therefore be infringing both claims simultaneously.
Does the method represent the "technology" to achieve the vibrator effect and the app itself as the "software"?
Sort of. A method represents the steps that are performed, generally independent of how they are performed. Software (such as an app) is a specific implementation of those steps.
What if I decided to build a new device or apparatus that will work only as a custom vibrator using the technology described. How will that fit into "method, apparatus, and/or computer software" terminology.
A new apparatus would be an apparatus claim.
Assume there is a granted patent with three claims:
A method comprising: sending a packet across a network.
- Infringed by: a person who performs the step of sending a packet across a network (regardless of how they do it).
An apparatus comprising: a network interface card configured to send a packet across a network.
- Infringed by: a person who makes, uses, offers to sell, or sells a network interface card
Software comprising instructions for sending a packet across a network.
- Infringed by: a person who sells firmware that allows a computer to send a packet across a network
Each person's actions only infringes one of the three claims. If you omitted any one of them, you would narrow your protection.