" The cereal guys buying condoms? Does it mean that they are not familiar with the area？ No. I haven't seen this episode, but Beck would be making a reference to guys who go to a shop to buy condoms but get embarrassed or are too shy to actually buy them. Instead of getting what they really want - a packet of condoms - they get too nervous or shy and grab something else like a box of breakfast cereal to justify being in the shop. 'own your shit' is idiom that generally means 'Admit it, don't dodge/evade it or try and skip responsibility. (All this is said in a lightly cursing, mocking manner). The exact nuance varies with context. 'be out about it' means 'be honest and in the open about it. Don't try and hide it from yourself or others.' "Like, own your shit.If Dan Brown's your kink, then be out about it." I haven't seen the episode, but my interpretation would be: "Get honest with yourself. Admit it. If Dan Brown's your kink then face up to it and don't hide it or ignore it."

These are both pretty informal phrases, slang in the first case, so you might struggle to find a proper dictionary definition. But I would take the meaning as something like this: Own your shit = Embrace and accept a situation honestly, instead of trying to hide it or be shy about it. be out about it = be honest about it (if you like Dan Brown, then just say you like Dan Brown, don't hide it).