she wants it to happen

you're sure Lois will agree with you but she surprises you
"i love you, jena, but you know we're few people remaining after the war... we should tryy to reproduce and grow in population again... I know before the war having only a couple was the rule, but nowadays we need to improve our chance. so, if she wants you she's my aproval but either ways you won't get free of me. we're a family... we'll have to share your sheed"
you can't refuse her arguments but it doesn't mean you like having to have sex with another girl
"all right you don't look convinced... i'll make this easier"
then she sits over your chest and starts kissing you "we'll have sex whole of us together"