Build the drum part around the vocal phrase
Hear the whole vocal phrase before choosing where to add movement.
A lyric can begin before the downbeat, continue across a section change or finish after the band chord. Listen for that shape before deciding where the drums should change. The words do not require silence underneath them, but they can help you hear why one fill fits and another feels distracting.
Mark the phrase, not only the section
Listen without playing and note where the chorus vocal begins. Does it enter on 1, start as a pickup in the previous bar, or wait until later? Mark where the phrase ends as well. Compare that with the band’s planned entrance.
If a vocal pickup runs through the transition, try keeping the groove under it before adding a fill. If there is a gap, try a short fill there. These are options to hear, not rules attached to certain words.
Compare the two versions
For a practice example, loop the final two verse bars and first two chorus bars of a song. Play the agreed groove throughout on the first take. On the second, add two eighth-note snare hits on "4 &" of the final verse bar and return on the next 1.
Listen with the vocal present. Did the fill point toward the entrance, compete with the pickup, or make you late? If it competes, shorten it, move it only with the band’s agreement, or use the uninterrupted groove.
Rehearse the last line too
A final lyric may need a held chord, a band accent or a quiet ending. Ask when the last drum hit belongs and how long it should ring. Run from the line before it so you practice hearing the phrase and following the cue together.