How to Use Str. Contains() with Multiple Expressions, in Pandas Dataframes?

I'm wondering if there is a more efficient way to use the str.contains() function in Pandas, to search for two partial strings at once. I want to search a given column in a dataframe for data that contains either "nt" or "nv". Right now, my code looks like this:

    df[df['Behavior'].str.contains("nt", na=False)]
    df[df['Behavior'].str.contains("nv", na=False)]

And then I append one result to another. What I'd like to do is use a single line of code to search for any data that includes "nt" OR "nv" OR "nf." I've played around with some ways that I thought should work, including just sticking a pipe between terms, but all of these result in errors. I've checked the documentation, but I don't see this as an option. I get errors like this:

    ---------------------------------------------------------------------------
    TypeError                                 Traceback (most recent call last)
    <ipython-input-113-1d11e906812c> in <module>()
    3 
    4 
    ----> 5 soctol = f_recs[f_recs['Behavior'].str.contains("nt"|"nv", na=False)]
    6 soctol

    TypeError: unsupported operand type(s) for |: 'str' and 'str'

Is there a fast way to do this? Thanks for any help, I am a beginner but am LOVING pandas for data wrangling.