“ ‘If a man has
sexual relations with a man as one does with a woman, both of them have done what is detestable. They are to be put to death; their blood will be on their own heads. (Leviticus 20:13) NIV
"If a man also lie with mankind, as he
lieth with a woman, both of them have committed an abomination: they shall surely be put to death; their blood shall be upon them. " (Leviticus 20:13) KJV
The word "lieth" is originally, שָׁכַב shâkab, shaw-kab'; a primitive root; to lie down (for rest, sexual connection, decease or any other purpose):—× at all, cast down, (lover-)lay (self) (down), (make to) lie (down, down to sleep, still with), lodge, ravish, take rest, sleep, stay. Strong's H7901.
It was used for lie down, for rest, sexual connection, or decease. But the context used specifically in Leviticus 20:13 is "sexual connection" per my logos bible software. Thus "sexual relations " is the appropriate meaning for "lieth".