Hello,
Not sure if it’ll work in every case, but you can try following (and still preserve nice look during header scrolling):
1. In Menu Item -> Navigation Label enter
<span class=”menu_first_line”>Text-1</span><span class=”menu_second_line”>Text-2</span>
2. in custom.css enter
.menu_first_line {
display: block;
float: left;
}
.menu_second_line{
display: block;
float: left;
margin-top: 15px;
position: absolute;
}

#mobile-advanced .menu_first_line {
float: none;
display: inline;
}

#mobile-advanced .menu_second_line {
display: inline;
float: none;
margin-left: 4px;
margin-top: 0;
position: relative;
}