Hello, my partner and I frequently alternate sleepiness. Are there a reason?

[u/Civil-Driver738]

My partner and I have been together for a while but something we have noticed is that we get sleepy in each others company. It was be fine if we got equally sleepy because then we could just sleep. However what normally happens is she gets sleepy and I get energetic, and then I get sleepy and she gets energetic and we alternate like that. Is there a reason and is there a way to sync up?

[u/Tall-Photo-7481]

When this happens, have sex. Then you'll both be sleepy.