Migrants in precarious situations are often initially accommodated by relatives or acquaintances. This situation leads them to experience the intimacy of others, which can appear as a burden and a source of concern that they seek to alleviate, avoid or even escape. In the sociological literature, however, these concerns of guests have been overshadowed by those of hosts. This article examines them in the case of newly arrived migrants staying with relatives or acquaintances in Brussels, Geneva and Rotterdam. It shows that migrants not only deal with their own intimacy, but also with the intimacy of others, that of their hosts, which they now have to concern themselves with in order not to make any mistakes when it comes to the “grammar of hospitality”.