If I am doing bedtime solo I will usually let DS watch a movie and have a later night (it doesn't happen that often here), that gives me time to get DD to bed and often DS will fall asleep in front of the movie (I turn all the lights down, set him up with a pillow and quilt so he can get comfy and cosy)

However when DS is tired and I need to put both to bed at the same time, I take them both into my bed and feed DD while cuddling DS and once one of them has fallen asleep, then I cuddle, stroke, pat the other to sleep. Once they are in a deep sleep I'll transfer them to their own beds.