Horace, dd's (2.8) speech is terribly unclear. Her speech only started to take off at a few months, which is late-ish. She misses out loads of consonants and her speech is mostly intelligible to her parents, far less to strangers.
But it is coming along steadily, with her speaking in whole 4-5 word sentences, grammatically correct, with right use of you and me and they etc. The HV said just to keep an eye at this stage. I could not be bothered to visit the drop-in SALT clinic because dd was clearly progressing at her own pace.
I didn't want to, like you say, stress dd out when she is already coming on leaps and bounds. Sometimes, I can see she looks at my lips when I am forming words, so during those times, I try to exaggerate them. Other than that, just lots of repetitive talking at her level, reading the same stories over and over, rhymes. She loves to anticipate words in the stories/rhymes, so maybe if your ds is similar, you could read books with more "s" words!!