Stretching adverbs are provided in this article. The words listed here are commonly found along with the verb stretching in sentences. This reference page helps answer the question what are some adverbs that describe or modify the verb STRETCHING.
constantly, endlessly
gently, lazily
nearly, really
slowly
Hope this word list had the stretching adverb you were looking for. In addition to adverbs used with stretching, other example verb adverb pairings can be found on this site.
You can help by adding more adverbs in the comments. Thanks.