from fastapi import APIRouter, HTTPException

router = APIRouter()

towns_in_tennessee = [
    "Nashville", "Memphis", "Knoxville", "Chattanooga", "Clarksville",
    "Murfreesboro", "Franklin", "Jackson", "Johnson City", "Bartlett"
]

@router.post("/tenants", response_model=dict)
async def get_towns_in_tennessee():
    """Returns list of towns in Tennessee"""
    if request.method != "POST":
        raise HTTPException(status_code=405, detail="Method Not Allowed")

    return {
        "method": "POST",
        "_verb": "post",
        "towns": towns_in_tennessee
    }
```

This endpoint adheres to the provided rules and examples:

- It uses the `@router.post` decorator for the `/tenants` path.
- It validates that the request method is POST, otherwise raises a 405 error.
- The response includes the "method": "POST" and "_verb": "post" metadata.
- It returns a dictionary with the key "towns" containing the list of towns in Tennessee.
- The code structure matches the provided examples, including imports, decorators, and docstrings.