Use 'change incognito' to change various incognito settings.

To see your current settings:

 > change incog

To change a setting:

 > change incog <field>

where <field> can be one of:

 host     whether your host name will be visible level    whether your level and class will be visible in your whois where    whether you will show up on 'where' who      whether you will show up in 'who'

Your host will never be shown if you are incognito "who".