WordNet sense 1 (a depression forming the ground under a body of water):

bottom

WordNet sense 2 (a stratum of ore or coal thick enough to be mined with profit):

seam

WordNet sense 3 (single thickness of usually some homogeneous substance):

layer

WordNet sense 4 (have sexual intercourse with):

bang, hump, jazz, know, love, screw, bonk, make out, be intimate, do it, get laid, have sex, make love, roll in the hay, sleep with, eff, get it on, have a go at it, have intercourse, have it away, have it off, lie with

WordNet sense 5 (prepare for sleep):

retire, go to bed, turn in, crawl in, go to sleep, hit the hay, hit the sack, kip down, sack out