I've been looking through past threads and it does seem a tough nut to crack as cockers are just so insanely social which is a good part of their appeal as a companion. He's so good with me, but his excitement level just goes off the scale when people come. And as you say, with people arriving at the door in different combinations, it's just too much to be dog wrangling/training at the same time as you have coats to take, bottle of wine to put in the kitchen etc. That does lead to another problem which is isolation also drives him mental and extremely vocal. In the past when I knew there would be a stream of people arriving, I tried putting him in the bedroom and he just howled the place down, trying to get attention and be let out into the company. I have vids from my Burns night with him whimpering and moaning at a high volume in the background from his penned state. He's such a vocal whiner, I'm thinking of trying to get him to shut up with clicker training. I just don't have the knack yet of dealing with hostessing and keeping my lovable monster under control. I can see people's smiles becoming fixed as he tries to crawl into their laps. Once again, as you say, once one person invites it and several of my friends do, he's ever hopeful everyone wants a lap dog and he's very insistent. The evening becomes a long set of instructions to the dog, off, sit, in your bed, each of which lasts until we're talking again and he's sneaking round the coffee table to crawl up beside someone to cuddle. In fact, he looks to the visitor as protection from my irritating demands for him to off of get in his bed. It's that or an evening long yahooing from another room.
