1 girl went to bed, went to bed with Barry
1 girl and her mate, went to bed with Barry.
2 girls went to bed, went to bed with Barry
2 girls, 1 girl and her mate, went to bed with Barry
3 girls went to bed, went to bed with Barry
3 girls, 2 girls, 1 girl and her mate, wen to bed with Barry
and so forth...