at irregular intervals
at random
brokenly
by catches
by fits
by jerks
by snatches
capriciously
cautiously
circumspectly
crawlingly
creepingly
deliberately
desultorily
dilatorily
disconnectedly
discontinuously
easily
eccentrically
erratically
falteringly
fitfully
gently
idly
in low gear
in march time
in slow motion
in slow tempo
in snatches
in spots
inconstantly
indolently
intermittently
irregularly
jerkily
languidly
languorously
leisurely
limpingly
lingeringly
loiteringly
lurchingly
moderately
nonuniformly
off and on
patchily
pokily
pokingly
relaxedly
reluctantly