I remember years ago asking the same question. I confess at the time, my thoughts were not pure and coming from selfish motives.
The activity which is described as an abomination in Leviticus and unnatural in romans is clearly not ok even for consenting husband and wife. It could be argued that anything beyond just intercourse is unnatural, so would be safer ground to avoid that activity also . We have to remember our life is spiritual , our flesh is dead to sin and the carnal world .
If you are desiring other such other activity beyond intercourse , from what motive is this arising , love or selfishness ? Even if it’s reciprocated , it’s dubious to see it as anything but selfishness