according to pleasure

extemporize extemporized impromptu improvise improvised

ad libitum as one thinks best as one wishes at will extemporaneous extempore made-up off-the-cuff spontaneous unprepared unrehearsed without restraint

deliberate planned prepared rehearsed written

ad-lib as one thinks best as one wishes at will extemporaneous freely impromptu improvised impulsive made-up off-the-cuff offhand spontaneously unrehearsed without restraint