Assess voice quality-- is the voice "wet"? Encourage cough to see what happens.
Oropharyngeal suction with a big honking Yankauer if secretions or liquids visible in there, turn on side (either side, whichever is faster) so anything else they vomit up runs out onto the pillow. Encourage deep breathing (IF PHARYNX IS CLEAR) and deep coughing.
Sit bolt upright if the patient can tolerate that, suction to clear airway, reassure, encourage good coughing if possible, watch like a hawk for deterioration.
Both: Once things stabilize a bit, listen to the chest, especially RML as that's the one with the straightest shot from the trachea, to see if there are new bubbles. Chest xray. Watch SpO2. Determine what went down there-- water, apple juice, vomitus, foreign body, food? Water or juice, not so bad. Oily medication? Very bad. Lipid pneumonia is very damaging. Vomitus? Acid is bad for lungs.